| **ACCUMULATED OTHER COMPREHENSIVE INCOME / (LOSS)**                      | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|--------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| ACCUMULATED OTHER COMPREHENSIVE INCOME / (LOSS)                          | ACCUMULATED OTHER COMPREHENSIVE INCOME / (LOSS)The following table presents the components of accumulated other comprehensive income/(loss), net of related tax, for the three-month periods endedMarch 31, 2016, and 2015, respectively.Total OtherComprehensive Income/(Loss)Total AccumulatedOther Comprehensive Income/(Loss)Three-Month Period Ended March 31, 2016December 31, 2015March 31, 2016PretaxActivityTaxEffectNet ActivityBeginningBalanceNetActivityEndingBalance(in thousands)Change in accumulated (losses)/gains on cash flow hedge derivative financial instruments$(79,875)$30,260$(49,615)   Reclassification adjustment for net gains/(losses) on cash flow hedge derivative financial instruments (1)2,663(1,255)1,408   Net unrealized (losses)/gains on cash flow hedge derivative financial instruments(77,212)29,005(48,207)$(16,582)$(48,207)$(64,789)Change in unrealized gains/(losses) on investment securities available-for-sale265,175(104,213)160,962   Reclassification adjustment for net(gains)/losses included in net income on non-OTTI securities (2)(26,431)10,387(16,044)Reclassification adjustment for net losses/(gains) included in net income on OTTI securities (3)10(4)6Reclassification adjustment for net (gains)/losses included in net income(26,421)10,383(16,038)   Net unrealized gains/(losses) on investment securities available-for-sale238,754(93,830)144,924(96,026)144,92448,898Pension and post-retirement actuarial gain/(loss) (4)929(364)565(27,033)565(26,468)As of March 31, 2016$162,471$(65,189)$97,282$(139,641)$97,282$(42,359)                        (1)  Net gains reclassified into Interest on borrowings and other debt obligations in the Condensed Consolidated Statement of Operations for settlements of interest rate swap contracts designated as cash flow hedges in Note 11 to the Condensed Consolidated Financial Statements. (2)  Net gains reclassified into Net gain on sale of investment securities in the Condensed 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 3 to the Condensed Consolidated Financial Statements.(4)  Included in the computation of net periodic pension costs. NOTE 13. ACCUMULATED OTHER COMPREHENSIVE INCOME / (LOSS) (continued) Total OtherComprehensive Income/(Loss) Total AccumulatedOther Comprehensive Income/(Loss) Three-Month Period Ended March 31, 2015 December 31, 2014   March 31, 2015 PretaxActivity TaxEffect Net Activity BeginningBalance NetActivity EndingBalance (in thousands)Change in accumulated (losses)/gains on cash flow hedge derivative financial instruments$(29,009) $11,154 $(17,855)      Reclassification adjustment for net gain/(losses) on cash flow hedge derivative financial instruments (1)4,451 (1,711) 2,740      Net unrealized (losses)/gains on cash flow hedge derivative financial instruments(24,558) 9,443 (15,115) $(14,260) $(15,115) $(29,375)            Change in unrealized gains/(losses) on investment securities available-for-sale117,781 (45,964) 71,817      Reclassification adjustment for net (gains)/losses included in net income on non-OTTI securities(2)(9,557) 3,730 (5,827)      Net unrealized gains/(losses) on investment securities available-for-sale108,224 (42,234) 65,990 (52,515) 65,990 13,475            Pension and post-retirement actuarial gain/(loss)(3)1,018 (403) 615 (29,635) 615 (29,020)            As of March 31, 2015$84,684 $(33,194) $51,490 $(96,410) $51,490 $(44,920)            (1)  Net gains reclassified into Interest on borrowings and other debt obligations in the Condensed Consolidated Statement of Operations for settlements of interest rate swap contracts designated as cash flow hedges in Note 11.(2)  Net gains reclassified into Net gains on sale of investment securities sales in the Condensed Consolidated Statement of Operations for the sale of available-for-sale securities.(3)  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
The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e689-108580Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669619-108580Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e640-108580Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e716-108580Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e709-108580Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e637-108580Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e681-108580Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Reclassification Adjustments -URI http://asc.fasb.org/extlink&oid=6522872
+ Details**Name:**us-gaap_ComprehensiveIncomeNoteTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |