Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidated Statements of Comprehensive Income
Net income	$ 25,801	$ 23,604	$ 22,953
Unrealized (losses) gains on securities available for sale:
Unrealized (losses) gains arising during the period (net of tax of $(24), $1,362, and $580, respectively)	(45)	2,530	1,076
Reclassification adjustment for securities gains realized in income (net of tax of $0, $0, and $(56), respectively)			(103)
Minimum pension liability adjustment (net of tax of $2, $(111), and $(17), respectively)	4	(207)	(33)
Other comprehensive (loss) income	(41)	2,323	940
Comprehensive income	$ 25,760	$ 25,927	$ 23,893