Securities (Details 4) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Available For Sale Securities, Amortized Cost
Total	$ 1,383,329	$ 1,367,261
Available For Sale Securities, Fair value
Total	1,378,186	1,353,401
Total debt securities [Member]
Available For Sale Securities, Amortized Cost
Due in one year or less	42,922	25,596
Due after one year through five years	326,600	263,553
Due after five years through ten years	217,791	313,245
Due after ten years	28,142	28,952
Total	615,455	631,346
Available For Sale Securities, Fair value
Due in one year or less	43,758	26,017
Due after one year through five years	333,219	271,303
Due after five years through ten years	213,881	304,414
Due after ten years	27,031	27,206
Total	617,889	628,940
Mortgage-backed securities [Member]
Available For Sale Securities, Amortized Cost
Total	767,874	735,915
Available For Sale Securities, Fair value
Total	$ 760,297	$ 724,461