Parent Company Financial Statements (Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Activities
Net Income	$ 23,428	$ 26,177	$ 24,766
Depreciation and amortization	4,707	3,703	3,189
Stock-based compensation expense	538	1,025	809
Decrease (increase) in other assets	150	(3,187)	(1,530)
Net cash provided by operating activities	42,329	33,423	35,808
Investing Activities
Purchase of premises and equipment	(3,403)	(1,516)	(2,459)
Net cash provided (used) by investing activities	32,138	14,802	(79,662)
Financing Activities
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit	(212)	(134)	114
Common stock repurchase	(2,097)	(389)	(49)
Cash dividends paid on common stock	(7,667)	(11,524)	(7,664)
Net increase in cash and cash equivalents	18,965	8,316	1,237
Cash and cash equivalents at beginning of year	39,325	31,009	29,772
Cash and cash equivalents at end of year	58,290	39,325	31,009
Parent Company [Member]
Operating Activities
Net Income	23,428	26,177	24,766
Equity in undistributed earnings of subsidiaries	(11,647)	(12,441)	(14,372)
Depreciation and amortization	1,196	1,194	1,182
Stock-based compensation expense	538	1,025	809
Increase in amount receivable from subsidiaries	(983)	(22)	(573)
Decrease (increase) in other assets	(1,334)	(35)	(1,962)
Increase in accrued expenses	636	3,522	1,992
Net cash provided by operating activities	11,834	19,420	11,842
Investing Activities
Purchase of premises and equipment	(1,009)	(1,286)	(2,759)
Net cash provided (used) by investing activities	(1,009)	(1,286)	(2,759)
Financing Activities
Exercise of stock options and issuance of restricted stock, net of repurchase for tax withholdings and tax benefit	(212)	(134)	114
Common stock repurchase	(2,097)	(389)	(49)
Cash dividends paid on common stock	(7,667)	(11,524)	(7,664)
Net Cash Provided by (Used in) Financing Activities, Continuing Operations, Total	(9,976)	(12,047)	(7,599)
Net increase in cash and cash equivalents	849	6,087	1,484
Cash and cash equivalents at beginning of year	18,661	12,574	11,090
Cash and cash equivalents at end of year	$ 19,510	$ 18,661	$ 12,574