Investment Securities (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 security	Dec. 31, 2012 security	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Trading securities	$ 0	$ 0
Held-to-maturity securities	0	0
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	440,557	365,755
Unrealized gains	2,928	8,236
Unrealized losses	(10,943)	(1,023)
Fair value	432,542	372,968
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	246,904	59,705
12 months or more, fair value	56,118	12,428
Total fair value	303,022	72,133
Less than 12 months, unrealized losses	(6,855)	(433)
12 months or more, unrealized losses	(4,088)	(590)
Unrealized losses	(10,943)	(1,023)
Number of securities temporarily impaired	96	25
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]
Three months or less, amortized cost	2,000
Over three months to one year, amortized cost	4,231
After one year through three years, amortized cost	54,220
After year three through five years, amortized cost	241,061
After five through ten years, amortized cost	80,002
After ten years, amortized cost	59,043
Total amortized cost	440,557
Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]
Three months or less, fair value	2,011
Over three months to one year, fair value	4,320
After one year through three years, fair value	55,008
After three years through five years, fair value	235,756
After five years through ten years, fair value	78,254
After ten years, fair value	57,193
Total cost - fair value	432,542
Pledged Financial Instruments, Not Separately Reported, Securities [Abstract]
To state and local governments to secure public deposits, amortized cost	71,045
To Federal Reserve Bank to secure borrowings, amortized cost	17,921
To Federal Home Loan Bank to secure borrowings, amortized cost	521
Other securities pledged, principally to secure deposits, amortized cost	12,568
Total pledged investment securities, amortized cost	102,055
Pledged Assets Separately Reported, Securities Pledged as Collateral, at Fair Value, by Type of Agreement [Abstract]
To state and local governments to secure public deposits, fair value	71,078
To Federal Reserve Bank to secure borrowings, fair value	17,865
To Federal Home Loan Bank to secure borrowings, fair value	539
Other securities pledged, principally to secure deposits, fair value	12,965
Total pledged investment securities, fair value	102,447
Gain on sale of investment securities [Abstract]
Gross realized gains	556	933	0
Gross realized losses	0	(2)	0
Gain on sale of investment securities, net	556	931	0
U.S. government agencies [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	85,631	87,297
Unrealized gains	706	1,321
Unrealized losses	(665)	(32)
Fair value	85,672	88,586
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	40,528	12,056
12 months or more, fair value	0	0
Total fair value	40,528	12,056
Less than 12 months, unrealized losses	(665)	(32)
12 months or more, unrealized losses	0	0
Unrealized losses	(665)	(32)
Residential pass-through securities [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	185,677	165,175
Unrealized gains	589	3,430
Unrealized losses	(5,457)	(182)
Fair value	180,809	168,423
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	110,071	27,680
12 months or more, fair value	31,494	0
Total fair value	141,565	27,680
Less than 12 months, unrealized losses	(3,262)	(182)
12 months or more, unrealized losses	(2,195)	0
Unrealized losses	(5,457)	(182)
Taxable state and political subdivisions [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	2,294	4,759
Unrealized gains	174	553
Unrealized losses	0	0
Fair value	2,468	5,312
Tax exempt state and political subdivisions [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	74,761	56,431
Unrealized gains	1,420	2,703
Unrealized losses	(1,374)	(149)
Fair value	74,807	58,985
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	35,360	10,113
12 months or more, fair value	6,593	0
Total fair value	41,953	10,113
Less than 12 months, unrealized losses	(990)	(149)
12 months or more, unrealized losses	(384)	0
Unrealized losses	(1,374)	(149)
Corporate obligations [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	11,000	11,000
Unrealized gains	21	0
Unrealized losses	(88)	(565)
Fair value	10,933	10,435
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	2,997	0
12 months or more, fair value	2,916	10,435
Total fair value	5,913	10,435
Less than 12 months, unrealized losses	(4)	0
12 months or more, unrealized losses	(84)	(565)
Unrealized losses	(88)	(565)
Agency-issued collateralized mortgage obligations [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	55,579	13,967
Unrealized gains	18	79
Unrealized losses	(1,452)	0
Fair value	54,145	14,046
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	49,230
12 months or more, fair value	0
Total fair value	49,230
Less than 12 months, unrealized losses	(1,452)
12 months or more, unrealized losses	0
Unrealized losses	(1,452)
Asset-backed securities [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	23,597	25,108
Unrealized gains	0	150
Unrealized losses	(1,781)	(70)
Fair value	21,816	25,188
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	8,718	9,856
12 months or more, fair value	13,097	0
Total fair value	21,815	9,856
Less than 12 months, unrealized losses	(482)	(70)
12 months or more, unrealized losses	(1,299)	0
Unrealized losses	(1,781)	(70)
Investments in mutual funds and other equities [Member]
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Amortized cost	2,018	2,018
Unrealized gains	0	0
Unrealized losses	(126)	(25)
Fair value	1,892	1,993
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Less than 12 months, fair value	0	0
12 months or more, fair value	2,018	1,993
Total fair value	2,018	1,993
Less than 12 months, unrealized losses	0	0
12 months or more, unrealized losses	(126)	(25)
Unrealized losses	$ (126)	$ (25)