Goodwill and Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Goodwill and Intangible Assets Gross Carrying Value [Abstract]
Goodwill not subject to amortization	$ 29,513	$ 29,513
Intangibles from branch acquisition	3,015	3,015
Core deposit intangibles	8,986	8,986
Customer list intangibles	1,904	1,904
Total Goodwill and Intangible Assets, Gross Carrying Value	43,418	43,418
Goodwill and Intangible Assets Accumulated Amortization [Abstract]
Goodwill not subject to amortization (effective 1/1/02), Accumulated Amortization	3,760	3,760
Total Goodwill and Intangible Assets, Accumulated Amortization	14,504	13,731
Total Amortization Expense [Abstract]
Amortization of intangible assets	773	1,134	814
Estimated amortization expense [Abstract]
For period ended 12/31/13	673
For period ended 12/31/14	643
For year ended 12/31/15	616
For year ended 12/31/16	381
For year ended 12/31/17	254
Intangibles from branch acquisitions
Goodwill and Intangible Assets Accumulated Amortization [Abstract]
Intangible Assets, Accumulated Amortization	3,015	2,965
Total Amortization Expense [Abstract]
Amortization of intangible assets	50	201	201
Core deposit intangibles
Goodwill and Intangible Assets Accumulated Amortization [Abstract]
Intangible Assets, Accumulated Amortization	5,825	5,119
Total Amortization Expense [Abstract]
Amortization of intangible assets	706	743	423
Customer list intangibles
Goodwill and Intangible Assets Accumulated Amortization [Abstract]
Intangible Assets, Accumulated Amortization	1,904	1,887
Total Amortization Expense [Abstract]
Amortization of intangible assets	$ 17	$ 190	$ 190