Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 6,637	$ 7,037	$ 22,227	$ 19,356
Securities:
Unrealized holding gains (losses) on securities	782	2,486	(6,091)	4,594
Reclassification adjustment for losses (gains) realized in net income	0	0	71	(1,095)
Amortization of unrealized holding gains on securities transferred to the held to maturity category	(49)	(83)	(169)	(276)
Total securities	733	2,403	(6,189)	3,223
Derivative instruments:
Unrealized holding (losses) gains on derivative instruments	(297)	(241)	902	(1,379)
Reclassification adjustment for gains realized in net income	(22)	(71)	(126)	(259)
Totals derivative instruments	(319)	(312)	776	(1,638)
Defined benefit pension and post-retirement benefit plans:
Net (loss) gain arising during the period	0	0	0	0
Less amortization of net actuarial loss recognized in net periodic pension cost	113	66	270	198
Total defined benefit pension and post-retirement benefit plans	113	66	270	198
Other comprehensive loss, net of tax	527	2,157	(5,143)	1,783
Comprehensive income	$ 7,164	$ 9,194	$ 17,084	$ 21,139