Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 5,236	$ 7,361	$ 6,325	$ 8,477	$ 4,722	$ 5,020	$ 5,321	$ 3,931	$ 27,399	$ 18,994	$ 18,590
Other comprehensive (loss) income, net of tax:
Unrealized holding (losses) gains on securities arising during the period									(2,452)	(1,216)	1,504
Change in minimum pension liability									1,750	(2)	1,140
Change in joint beneficiary agreement liability									400	(434)	(143)
Other comprehensive (loss) income									(302)	(1,652)	2,501
Comprehensive income									$ 27,097	$ 17,342	$ 21,091