Other Comprehensive Income - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Securities available for sale:
Unrealized holding gains on securities, pre-tax	$ 1,326	$ (6,212)	$ 6,315	$ (1,963)
Reclassification adjustment for gains realized in net income, pre-tax	(1,257)	(96)	(1,186)	(96)
Amortization of unrealized holding gains on securities transferred to the held to maturity category, pre-tax	(28)	(46)	(61)	(97)
Total securities available for sale, pre-tax	41	(6,354)	5,068	(2,156)
Unrealized holding gains (losses) on securities, tax expense (benefit)	514	(2,376)	2,440	(751)
Reclassification adjustment for gains realized in net income, tax expense (benefit)	(485)	(36)	(458)	(36)
Amortization of unrealized holding gains on securities transferred to the held to maturity category, tax expense (benefit)	(10)	(18)	(23)	(37)
Total securities available for sale, tax expense (benefit)	19	(2,430)	1,959	(824)
Net change in unrealized holding gains on securities	812	(3,836)	3,875	(1,212)
Reclassification adjustment for gains realized in net income	(772)	(60)	(728)	(60)
Amortization of unrealized holding gains on securities transferred to the held to maturity category	(18)	(28)	(38)	(60)
Total securities	22	(3,924)	3,109	(1,332)
Derivative instruments:
Unrealized holding gains (losses) on derivative instruments, pre-tax	(704)	1,399	(2,766)	315
Total derivative instruments, pre-tax	(704)	1,399	(2,766)	315
Unrealized holding gains on derivatives, tax expense (benefit)	(276)	536	(1,072)	121
Total derivative instruments, tax expense (benefit)	(276)	536	(1,072)	121
Unrealized holding gains (losses) on derivative instruments	(428)	863	(1,694)	194
Totals derivative instruments	(428)	863	(1,694)	194
Defined benefit pension and post-retirement benefit plans:
Amortization of net actuarial loss recognized in net periodic pension cost, pre-tax	119	109	236	202
Total defined benefit pension and post-retirement benefit plans, pre-tax	119	109	236	202
Amortization of net actuarial loss recognized in net periodic pension cost, tax expense (benefit)	39	41	84	77
Total defined benefit pension and post-retirement benefit plans, tax expense (benefit)	39	41	84	77
Amortization of net actuarial loss recognized in net periodic pension cost	80	68	152	125
Total defined benefit pension and post-retirement benefit plans	80	68	152	125
Total other comprehensive income (loss), pre-tax	(544)	(4,846)	2,538	(1,639)
Total other comprehensive income (loss), tax expense (benefit)	(218)	(1,853)	971	(626)
Other comprehensive (loss) income, net of tax	$ (326)	$ (2,993)	$ 1,567	$ (1,013)