Securities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	$ 432,075	$ 431,522
Gross Unrealized Gains	4,388	3,489
Gross Unrealized Losses	(8,838)	(12,026)
Fair Value	427,625	422,985
Corporate bonds
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	1,642	1,540
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(11)	(15)
Fair Value	1,632	1,525
U.S. Treasury and U.S. government sponsored entities
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	49,229	50,942
Gross Unrealized Gains	646	755
Gross Unrealized Losses	(317)	(387)
Fair Value	49,558	51,310
State and political subdivisions
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	95,823	96,239
Gross Unrealized Gains	1,803	1,302
Gross Unrealized Losses	(1,917)	(2,807)
Fair Value	95,709	94,734
Mortgage-backed securities - residential
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	230,785	226,865
Gross Unrealized Gains	1,713	1,199
Gross Unrealized Losses	(3,428)	(5,084)
Fair Value	229,070	222,980
Collateralized mortgage obligations
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	29,263	30,227
Gross Unrealized Gains	145	162
Gross Unrealized Losses	(1,443)	(1,713)
Fair Value	27,965	28,676
Small business administration
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	25,215	25,592
Gross Unrealized Gains	1	1
Gross Unrealized Losses	(1,721)	(2,020)
Fair Value	23,495	23,573
Equity securities
Amortized cost and fair value of available-for-sale investment securities
Amortized Cost	118	117
Gross Unrealized Gains	79	70
Gross Unrealized Losses	(1)	0
Fair Value	$ 196	$ 187