Other Comprehensive Income - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Securities:
Unrealized holding gains on securities, Pre-Tax	$ (6,212)	$ 1,953	$ (1,963)	$ 6,462
Reclassification adjustment for gains realized in net income, Pre-Tax	(96)		(96)	0
Amortization of unrealized holding gains on securities transferred to the held to maturity category, Pre-Tax	(46)	(64)	(97)	(135)
Total securities available for sale, Pre-Tax	(6,354)	1,889	(2,156)	6,327
Unrealized holding gains on securities, Tax Expense (Benefit)	(2,376)	747	(751)	2,472
Reclassification adjustment for gains realized in net income, Pre-Tax	(36)		(36)	0
Amortization of unrealized holding gains on securities transferred to the held to maturity category, Tax Expense (Benefit)	(18)	(25)	(37)	(52)
Total securities available for sale, Tax Expense (Benefit)	(2,430)	722	(824)	2,420
Net change in unrealized holding (losses) gains on securities	(3,836)	1,206	(1,212)	3,990
Reclassification adjustment for gains realized in net income	(60)	0	(60)	0
Amortization of unrealized holding gains on securities transferred to the held to maturity category	(28)	(39)	(60)	(83)
Total securities	(3,924)	1,167	(1,332)	3,907
Derivative instruments:
Unrealized holding losses on derivative instruments, Pre-Tax	1,399	(641)	315	(1,320)
Total derivative instruments, Pre-Tax	1,399	(641)	315	(1,320)
Unrealized holding gains on derivative instruments, Tax Expense (Benefit)	536	(245)	121	(505)
Total derivative instruments, Tax Expense (Benefit)	536	(245)	121	(505)
Unrealized holding gains (losses) on derivative instruments	863	(396)	194	(815)
Totals derivative instruments	863	(396)	194	(815)
Defined benefit pension and post-retirement benefit plans:
Amortization of net actuarial loss recognized in net periodic pension cost, Pre-Tax	109	73	202	146
Total defined benefit pension and post-retirement benefit plans, Pre-Tax	109	73	202	146
Amortization of net actuarial loss recognized in net periodic pension cost, Tax Expense (Benefit)	41	28	77	56
Total defined benefit pension and post-retirement benefit plans, Tax Expense (Benefit)	41	28	77	56
Less amortization of net actuarial loss recognized in net periodic pension cost	68	45	125	90
Total defined benefit pension and post-retirement benefit plans	68	45	125	90
Total other comprehensive income, Pre-Tax	(4,846)	1,321	(1,639)	5,153
Total other comprehensive income, Tax Expense (Benefit)	(1,853)	505	(626)	1,971
Other comprehensive (loss) income, net of tax	$ (2,993)	$ 816	$ (1,013)	$ 3,182