Parent Company (Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Net income	$ 15,194	$ 14,620	$ 15,461
Net change in other assets	(2,333)	2,130	(877)
Net change in other liabilities	(11,282)	8,726	(5,888)
Net cash provided by operating activities	5,662	31,393	12,334
Sale of treasury stock	18	14	10
Proceeds from exercise of stock options	280	0	59
Tax benefit from exercises of stock options	20	1	2
Cash dividends paid	(6,324)	(6,233)	(6,139)
Net cash provided by (used in) financing activities	92,321	98,475	44,374
Increase (decrease) in cash and cash equivalents	39,416	(36,214)	(520)
Cash and cash equivalents beginning of period	37,812	74,026	74,546
Cash and cash equivalents end of period	77,228	37,812	74,026
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	15,194	14,620	15,461
Net change in other assets	170	(84)	(187)
Net change in other liabilities	(116)	66	201
Equity in undistributed earnings of subsidiaries	(8,721)	(7,832)	(9,705)
Net cash provided by operating activities	6,527	6,770	5,770
Sale of treasury stock	18	14	10
Proceeds from exercise of stock options	280	(1)	59
Tax benefit from exercises of stock options	20	1	2
Cash dividends paid	(6,324)	(6,233)	(6,139)
Other, net	200	206	208
Net cash provided by (used in) financing activities	(5,806)	(6,013)	(5,860)
Increase (decrease) in cash and cash equivalents	721	757	(90)
Cash and cash equivalents beginning of period	3,395	2,638	2,728
Cash and cash equivalents end of period	$ 4,116	$ 3,395	$ 2,638