Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 5,682	$ 4,582	$ 14,261	$ 12,504
Unrealized gains on securities:
Unrealized holding gains arising during period	2,628	4,469	5,336	8,121
Less: reclassification adjustment for gains included in net income	(529)	(883)	(1,119)	(1,245)
Total unrealized gains(losses) on securities	2,099	3,586	4,217	6,876
Defined benefit pension plans:
Amortization of prior service cost and loss included in net periodic benefit cost	163	95	487	285
Other comprehensive income	2,262	3,681	4,704	7,161
Comprehensive income	$ 7,944	$ 8,263	$ 18,965	$ 19,665