Investment Securities - Amortized Cost and Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities
Amortized Cost, After 1 but within 5 years		$ 648
Amortized Cost, Total available-for-sale securities	374,680	336,349
Unrealized Gains	7,913	7,766
Unrealized Losses	1,747	995
Fair Value, Total available-for-sale securities	380,846	343,120	[1]
Securities of U.S. government agencies
Schedule of Available-for-sale Securities
Amortized Cost, Within 1 year		10,005
Amortized Cost, After 1 but within 5 years	17,191	17,479
Amortized Cost	17,191	27,484
Unrealized Gains	46	44
Unrealized Losses	5	1
Fair Value, Within 1 year		10,020
Fair Value, After 1 but within 5 years	17,232	17,507
Fair Value	17,232	27,527
Government sponsored agencies - Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Amortized Cost, Within 1 year	62	119
Amortized Cost, After 1 but within 5 years	282	315
Amortized Cost, After 5 but within 10 years	9,648	10,371
Amortized Cost, After 10 years	120,433	94,319
Amortized Cost	130,425	105,124
Unrealized Gains	2,399	2,458
Unrealized Losses	400	325
Fair Value, Within 1 year	63	121
Fair Value, After 1 but within 5 years	304	341
Fair Value, After 5 but within 10 years	9,976	10,712
Fair Value, After 10 years	122,081	96,083
Fair Value	132,424	107,257
Government sponsored agencies - Collateralized mortgage obligations
Schedule of Available-for-sale Securities
Amortized Cost, After 5 but within 10 years	9,686	9,975
Amortized Cost, After 10 years	93,552	111,155
Amortized Cost	103,238	121,778
Unrealized Gains	1,797	1,110
Unrealized Losses	85	295
Fair Value, After 1 but within 5 years		650
Fair Value, After 5 but within 10 years	9,946	10,178
Fair Value, After 10 years	95,004	111,765
Fair Value	104,950	122,593
Private label collateralized mortgage obligations
Schedule of Available-for-sale Securities
Amortized Cost, After 5 but within 10 years	172	178
Amortized Cost, After 10 years	10,535	848
Amortized Cost	10,707	1,026
Unrealized Gains	25	19
Unrealized Losses	76	0
Fair Value, After 5 but within 10 years	171	178
Fair Value, After 10 years	10,485	867
Fair Value	10,656	1,045
State and municipal securities
Schedule of Available-for-sale Securities
Amortized Cost, Within 1 year	620	620
Amortized Cost, After 1 but within 5 years	6,508	5,734
Amortized Cost, After 5 but within 10 years	29,486	24,464
Amortized Cost, After 10 years	76,417	50,031
Amortized Cost	113,031	80,849
Unrealized Gains	3,585	4,089
Unrealized Losses	1,181	373
Fair Value, Within 1 year	622	626
Fair Value, After 1 but within 5 years	6,872	6,055
Fair Value, After 5 but within 10 years	30,977	26,150
Fair Value, After 10 years	76,964	51,734
Fair Value	115,435	84,565
Common and preferred stocks
Schedule of Available-for-sale Securities
Amortized Cost, Common and preferred stocks	88	88
Unrealized Gains	61	46
Unrealized Losses	0	1
Fair Value, Common and preferred stocks	149	133
Within 1 year | Securities of U.S. government agencies
Schedule of Available-for-sale Securities
Unrealized Gains		15
Unrealized Losses		0
Within 1 year | Government sponsored agencies - Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Unrealized Gains	1	2
Unrealized Losses	0	0
Within 1 year | State and municipal securities
Schedule of Available-for-sale Securities
Unrealized Gains	2	6
Unrealized Losses	0	0
After 1 but within 5 years | Securities of U.S. government agencies
Schedule of Available-for-sale Securities
Unrealized Gains	46	29
Unrealized Losses	5	1
After 1 but within 5 years | Government sponsored agencies - Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Unrealized Gains	22	26
Unrealized Losses	0	0
After 1 but within 5 years | Government sponsored agencies - Collateralized mortgage obligations
Schedule of Available-for-sale Securities
Unrealized Gains		2
Unrealized Losses		0
After 1 but within 5 years | State and municipal securities
Schedule of Available-for-sale Securities
Unrealized Gains	364	321
Unrealized Losses	0	0
After 5 but within 10 years | Government sponsored agencies - Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Unrealized Gains	328	341
Unrealized Losses	0	0
After 5 but within 10 years | Government sponsored agencies - Collateralized mortgage obligations
Schedule of Available-for-sale Securities
Unrealized Gains	260	206
Unrealized Losses	0	3
After 5 but within 10 years | Private label collateralized mortgage obligations
Schedule of Available-for-sale Securities
Unrealized Gains	0	0
Unrealized Losses	1	0
After 5 but within 10 years | State and municipal securities
Schedule of Available-for-sale Securities
Unrealized Gains	1,645	1,698
Unrealized Losses	154	12
After 10 years | Government sponsored agencies - Residential mortgage-backed securities
Schedule of Available-for-sale Securities
Unrealized Gains	2,048	2,089
Unrealized Losses	400	325
After 10 years | Government sponsored agencies - Collateralized mortgage obligations
Schedule of Available-for-sale Securities
Unrealized Gains	1,537	902
Unrealized Losses	85	292
After 10 years | Private label collateralized mortgage obligations
Schedule of Available-for-sale Securities
Unrealized Gains	25	19
Unrealized Losses	75	0
After 10 years | State and municipal securities
Schedule of Available-for-sale Securities
Unrealized Gains	1,574	2,064
Unrealized Losses	$ 1,027	$ 361

[1] Derived from audited consolidated financial statements