Condensed Financial Information (Parent Company Only) (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Income (Expense)
Other income									$ 466	$ 102	$ 1,008
Interest expense	(3,457)	(3,720)	(3,517)	(3,628)	(3,868)	(4,020)	(4,249)	(4,364)	(14,322)	(16,501)	(20,875)
Employee benefit expense									(28,383)	(22,875)	(22,090)
Other expense									(54,024)	(46,147)	(42,571)
Income Before Undistributed Income of Subsidiaries									27,989	16,983	13,397
Income Tax Benefit									8,446	4,186	2,942
Net income	5,170	4,850	4,910	4,613	3,522	3,417	3,093	2,765	19,543	12,797	10,455
Preferred stock dividend and discount accretion									(481)	(1,325)	(1,406)
Net Income Available to Common Shareholders	5,014	4,787	4,804	4,457	3,460	2,707	2,816	2,489	19,062	11,472	9,049
Parent Company [Member]
Operating Income (Expense)
Dividend income from Bank									16,500	10,000	5,000
Investment income										4	6
Other income										17	200
Interest expense									(1,950)	(1,821)	(1,688)
Employee benefit expense									(695)	(535)	(498)
Other expense									(200)	(134)	(179)
Income Before Undistributed Income of Subsidiaries									13,655	7,531	2,841
Undistributed Income of Subsidiaries									4,766	4,288	6,759
Income Before Tax									18,421	11,819	9,600
Income Tax Benefit									1,122	978	855
Net income									19,543	12,797	10,455
Preferred stock dividend and discount accretion									(481)	(1,325)	(1,406)
Net Income Available to Common Shareholders									$ 19,062	$ 11,472	$ 9,049