| **Investment Securities (Tables)**                                 | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
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| **Investments, Debt and Equity Securities [Abstract]**             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Schedule of Available-for-sale Securities Reconciliation           | The following table summarizes the amortized cost and estimated fair value of investment securities and presents the related gross unrealized gains and losses:September 30, 2013        (dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair ValueAvailable for Sale:        Obligations of:        U.S. government sponsored enterprises $2,057 $25 $— $2,082Residential mortgage-backed securities-GSE 373,860 945 17,358 357,447Residential mortgage-backed securities-Private 20,484 784 10 21,258Commercial mortgage backed securities-GSE 22,863 — 1,219 21,644Commercial mortgage-backed securities-Private 10,419 — 786 9,633Business Development Company investment 1,753 887 — 2,640Corporate notes 24,874 134 — 25,008Total available for sale $456,310 $2,775 $19,373 $439,712Held to Maturity:        Residential mortgage-backed securities-GSE 143,611 — 6,556 137,055Commercial mortgage-backed securities-Private 10,073 — 654 9,419     Total held to maturity $153,684 $— $7,210 $146,474Total investment securities $609,994 $2,775 $26,583 $586,186         December 31, 2012        (dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair ValueAvailable for Sale:        Obligations of:        U.S. Treasury and government agencies $6,646 $335 $— $6,981U.S. government sponsored enterprises 22,118 55 — 22,173States and political subdivisions 5,918 120 — 6,038Residential mortgage-backed securities-GSE 436,344 5,678 948 441,074Residential mortgage-backed securities-Private 22,649 750 454 22,945Commercial mortgage backed securities-GSE 23,150 209 — 23,359Commercial mortgage backed securities-Private 5,283 34 — 5,317Corporate notes 36,710 270 17 36,963Total $558,818 $7,451 $1,419 $564,850 |
| Available-for-sale Securities, Continuous Unrealized Loss Position | The following tables show our investments' estimated fair value and gross unrealized losses, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position, at September 30, 2013 and December 31, 2012.  The change in unrealized losses during the three and nine month periods ending September 30, 2013 was attributed to changes in interest rates and not to changes in the credit quality of these securities. All unrealized losses on investment securities are considered by management to be temporary given the credit quality of these investment securities or the short duration of the unrealized loss, or both. Less than 12 Months 12 Months or More Total(dollars in thousands)Estimated Fair ValueGross Unrealized Losses Estimated Fair ValueGross Unrealized Losses Estimated Fair ValueGross Unrealized LossesSeptember 30, 2013        Available for Sale:        Residential mortgage-backed securities-GSE$312,145$17,358 $—$— $312,145$17,358Residential mortgage-backed securities-Private1,35010 —— 1,35010Commercial mortgage-backed securities-GSE21,6441,219 —— 21,6441,219Commercial mortgage-backed securities-Private9,633786 —— 9,633786Total available for sale$344,772$19,373 $—$— $344,772$19,373Held to Maturity:        Residential mortgage-backed securities-GSE$137,055$6,556 $—$— $137,055$6,556Commercial mortgage-backed securities-Private9,419654 —— 9,419654Total held to maturity$146,474$7,210 $—$— $146,474$7,210Total$491,246$26,583 $—$— $491,246$26,583         December 31, 2012        Obligations of:        Residential mortgage-backed securities-GSE$123,489$904 $7,027$44 $130,516$948Residential mortgage-backed securities-Private7,499454 —— 7,499454Corporate notes3,24917 —— 3,24917Total$134,237$1,375 $7,027$44 $141,264$1,419                                                                                                                                                                                                                                                                                                                     |
| Available-for-sale Securities, by Maturity Dates                   | The aggregate amortized cost and fair value of securities at September 30, 2013, by remaining contractual maturity, are shown in the following table.  Actual expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations.  Available-for-Sale Held-to-Maturity(dollars in thousands) Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair ValueDue in one year or less $16,486 $16,539 $— $—Due after one year through five years 10,445 10,551 — —With no stated maturity 1,753 2,640 — —Total 28,684 29,730 — —Mortgage-backed securities 427,626 409,982 153,684 146,474Total $456,310 $439,712 $153,684 $146,474                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |

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| - Definition
Tabular disclosure of fair value of investments in debt and equity securities in an unrealized loss position categorized neither as held-to-maturity nor trading securities.
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Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments.
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| - Definition
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No definition available.
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