Investment Securities (Amortized Cost and Fair Value of Available for Sale Securities and Held to Maturity Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Due in one year or less	$ 2,811
Due after one through five years	15,341
Due after five through ten years	55,107
Due after ten years	88,521
Available-For-Sale Securities, Debt Maturity, with Single Maturity Date, Amortized Cost, Total	161,780
Total Investment Securities	520,793
Due in one year or less	2,866
Due after one through five years	16,043
Due after five through ten years	58,080
Due after ten years	87,637
Available-For-Sale Securities, Debt Maturity, with Single Maturity Date, Fair Value, Total	164,626
Total Investment Securities	532,867
Due in one year or less	1,755
Due after one through five years	4,929
Due after five through ten years	55,406
Due after ten years	50,300
Held-To-Maturity Securities, Debt Maturities, with Single Maturity Date, Net Carrying Amount, Total	112,390
Total Investment Securities	336,696
Due in one year or less	1,759
Due after one through five years	5,295
Due after five through ten years	57,228
Due after ten years	52,227
Held-To-Maturity Securities, Debt Maturity, with Single Maturity Date, Fair Value, Total	116,509
Total Investment Securities	351,439
U.S. Government-sponsored mortgage-backed securities
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Without single maturity date	357,307
Without single maturity date	366,535
Without single maturity date	224,306
Without single maturity date	234,930
Equity Securities
Schedule of Available for sale Securities and Held to maturity Securities [Line Items]
Without single maturity date	1,706
Without single maturity date	$ 1,706