Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Net income	$ 8,019	$ 6,345	$ 15,590	$ 12,319
Securities:
Unrealized holding (losses) gains on securities	(7,019)	1,090	(6,873)	2,108
Reclassification adjustment for (gains) losses realized in net income	0	(537)	71	(1,095)
Amortization of unrealized holding gains on securities transferred to the held to maturity category	(54)	(91)	(120)	(193)
Total securities	(7,073)	462	(6,922)	820
Derivative instruments:
Unrealized holding gains (losses) on derivative instruments	992	(1,027)	1,199	(1,138)
Reclassification adjustment for gains realized in net income	(51)	(94)	(104)	(188)
Totals derivative instruments	941	(1,121)	1,095	(1,326)
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	(85)	(66)	(157)	(132)
Total defined benefit pension and post-retirement benefit plans	85	66	157	132
Other comprehensive loss, net of tax	(6,047)	(593)	(5,670)	(374)
Comprehensive income	$ 1,972	$ 5,752	$ 9,920	$ 11,945