| **ACCUMULATED OTHER COMPREHENSIVE INCOME / (LOSS) (Tables)**             | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|--------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| Schedule of Accumulated Other Comprehensive Income (Loss)                | The following table presents the components of accumulated other comprehensive income/(loss), net of related tax, for the years endedDecember 31, 2015, 2014 and 2013, respectively.             Total OtherComprehensive Loss Total AccumulatedOther Comprehensive Loss For the Year Ended December 31, 2015 December 31, 2014  December 31, 2015 PretaxActivity TaxEffect Net Activity BeginningBalance NetActivity EndingBalance (in thousands)Change in accumulated (losses)/gains on cash flow hedge derivative financial instruments$(15,074) $5,013 $(10,061)      Reclassification adjustment for net gains/(losses) on cash flow hedge derivative financial instruments (1)11,595 (3,856) 7,739      Net unrealized (losses)/gains on cash flow hedge derivative financial instruments(3,479) 1,157 (2,322) $(14,260) $(2,322) $(16,582)            Change in unrealized (losses)/gains on investment securities available-for-sale(53,390) 20,388 (33,002)      Reclassification adjustment for net (gains)/losses included in net income/(expense) on non-OTTI securities (2)(18,094) 6,910 (11,184)      Reclassification adjustment for net losses/(gains) included in net income/(expense) on OTTI securities (3)1,092 (417) 675      Total reclassification adjustment for net (gains)/losses included in net income (17,002) 6,493 (10,509)      Net unrealized (losses)/gains on investment securities available-for-sale(70,392) 26,881 (43,511) (52,515) (43,511) (96,026)            Pension and post-retirement actuarial gain/(loss) (4)4,487 (1,885) 2,602 (29,635) 2,602 (27,033)            As of December 31, 2015$(69,384)$26,153$(43,231)$(96,410)$(43,231)$(139,641)(1)  Net losses reclassified into Interest on borrowings and other debt obligations in the Consolidated Statement of Operations for settlements of interest rate swap contracts designated as cash flow hedges. (2)  Net gains reclassified into Net gain on sale of investment securities in the Consolidated Statement of Operations for the sale of available-for-sale securities. (3)  Unrealized losses previously recognized in accumulated other comprehensive income on securities for which OTTI was recognized during the period. See further discussion in Note 4 to the Consolidated Financial Statements.(4)  Included in the computation of net periodic pension costs.             NOTE 14. ACCUMULATED OTHER COMPREHENSIVE INCOME / (LOSS) (continued)             Total OtherComprehensive Income Total AccumulatedOther Comprehensive Loss For the Year Ended December 31, 2014 December 31, 2013   December 31, 2014 PretaxActivity TaxEffect Net Activity BeginningBalance NetActivity EndingBalance (in thousands)Change in accumulated gains/(losses) on cash flow hedge derivative financial instruments$(13,788) $5,038 $(8,750)      Reclassification adjustment for net gains/(losses) on cash flow hedge derivative financial instruments (1)53,440 (19,527) 33,913      Net unrealized gains/(losses) on cash flow hedge derivative financial instruments39,652 (14,489) 25,163 $(39,423) $25,163 $(14,260)            Change in unrealized gains/(losses) on investment securities available-for-sale268,050 (104,563) 163,487      Reclassification adjustment for net gains included in net income/(expense) on non-OTTI securities(2)(27,234) 10,624 (16,610)      Net unrealized gains/(losses) on investment securities available-for-sale240,816 (93,939) 146,877 (199,392) 146,877 (52,515)            Pension and post-retirement actuarial gain/(loss)(3)(23,799) 9,717 (14,082) (15,553) (14,082) (29,635)            As of December 31, 2014$256,669 $(98,711) $157,958 $(254,368) $157,958 $(96,410)(1)  Net losses reclassified into Interest on borrowings and other debt obligations in the Consolidated Statement of Operations for settlements of interest rate swap contracts designated as cash flow hedges. (2)  Net gains reclassified into Net gain on sale of investment securities in the Consolidated Statement of Operations for the sale of available-for-sale securities. (3)  Included in the computation of net periodic pension costs. NOTE 14. ACCUMULATED OTHER COMPREHENSIVE INCOME / (LOSS) (continued) Total OtherComprehensive Loss Total AccumulatedOther Comprehensive Loss For the Year Ended December 31, 2013 January 1, 2013   December 31, 2013 PretaxActivity TaxEffect Net Activity BeginningBalance NetActivity EndingBalance (in thousands)Change in accumulated gains/(losses) on cash flow hedge derivative financial instruments$2,041 $(655) $1,386      Reclassification adjustment for net gains/(losses) on cash flow hedge derivative financial instruments (1)65,145 (26,780) 38,365      Net unrealized gains/(losses) on cash flow hedge derivative financial instruments67,186 (27,435) 39,751 $(79,174) $39,751 $(39,423)Change in unrealized gains/(losses) on investment securities available-for-sale(584,681) 230,787 (353,894)      Reclassification adjustment for net gains/(losses) included in net income on non-OTTI securities (2)(73,084) 28,848 (44,236)      Reclassification adjustment for net gains/(losses) included in net income on OTTI securities (3)63,630 (25,116) 38,514      Total reclassification adjustment for net gains/(losses) included in net income(9,454) 3,732 (5,722)      Net unrealized gains/(losses) on investment securities available-for-sale(594,135) 234,519 (359,616) 160,224 (359,616) (199,392)Amortization of defined benefit plans(4)18,566 (7,403) 11,163 (26,716) 11,163 (15,553)As of December 31, 2013$(508,383) $199,681 $(308,702) $54,334 $(308,702) $(254,368) (1)  Net losses reclassified into Interest on borrowings and other debt obligations in the Consolidated Statement of Operations for the settlements of interest rate swap contracts designated as cash flow hedges.(2)  Net gains reclassified into Net gain on sale of investment securities in the Consolidated Statement of Operations for the sale of available-for-sale securities.(3)  Unrealized losses previously recognized in accumulated other comprehensive income on securities for which OTTI was recognized during the period.(4)  Included in the computation of net periodic pension costs. |

| X                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
+ Details**Name:**us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTaxAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Tabular disclosure of the components of accumulated other comprehensive income (loss).
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669686-108580
+ Details**Name:**us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |