Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 15,535	$ 6,637	$ 43,985	$ 22,227
Securities:
Net change in unrealized holding gains (losses) on securities	866	782	4,856	(6,091)
Reclassification adjustment for (gains) losses realized in net income	(232)	0	(232)	71
Amortization of unrealized holding losses on securities transferred to the held to maturity category	(38)	(49)	(121)	(169)
Total securities	596	733	4,503	(6,189)
Derivative instruments:
Net change in unrealized holding (losses) gains on derivative instruments	42	(297)	(773)	902
Reclassification adjustment for gains realized in net income	0	(22)	0	(126)
Totals derivative instruments	42	(319)	(773)	776
Defined benefit pension and post-retirement benefit plans:
Net gain arising during the period	0	0	0	0
Less amortization of net actuarial loss recognized in net periodic pension cost	47	113	137	270
Total defined benefit pension and post-retirement benefit plans	47	113	137	270
Other comprehensive income (loss), net of tax	685	527	3,867	(5,143)
Comprehensive income	$ 16,220	$ 7,164	$ 47,852	$ 17,084