| **Investment Securities (Tables)**                                 | 6 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:June 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 $2,063 $21 $— $2,084Residential mortgage-backed securities-GSE 386,628 1,013 18,658 368,983Residential mortgage-backed securities-Private 21,220 1,614 10 22,824Commercial mortgage backed securities-GSE 22,959 — 1,461 21,498Commercial mortgage-backed securities-Private 10,430 — 855 9,575Corporate notes 28,242 204 — 28,446Total available for sale $471,542 $2,852 $20,984 $453,410Held to Maturity:        Residential mortgage-backed securities-GSE 144,723 — 5,324 139,399Commercial mortgage-backed securities-Private 10,074 — 728 9,346     Total held to maturity $154,797 $— $6,052 $148,745Total investment securities $626,339 $2,852 $27,036 $602,155         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 June 30, 2013 and December 31, 2012.  The change in unrealized losses during the three and six month periods ending June 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 ratings on 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 LossesJune 30, 2013        Available for Sale:        Residential mortgage-backed securities-GSE$322,395$18,658 $—$— $322,395$18,658Residential mortgage-backed securities-Private—— 64310 64310Commercial mortgage-backed securities-GSE21,4981,461 —— 21,4981,461Commercial mortgage-backed securities-Private9,575855 —— 9,575855Total available for sale$353,468$20,974 $643$10 $354,111$20,984Held to Maturity:        Residential mortgage-backed securities-GSE$119,794$5,324 $—$— $119,794$5,324Commercial mortgage-backed securities-Private9,346728 —— 9,346728Total held to maturity$129,140$6,052 $—$— $129,140$6,052Total$482,608$27,026 $643$10 $483,251$27,036         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 June 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 $8,139 $8,193 $— $—Due after one year through five years 18,884 18,994 — —Due after five years through 10 years 3,282 3,342 — —Due after 10 years — — — —Total 30,305 30,529 — —Mortgage-backed securities 441,237 422,881 154,797 148,745Total $471,542 $453,410 $154,797 $148,745                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |

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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
Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value.
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No definition available.
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