Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total other comprehensive income (loss), pre-tax	$ (10,400)	$ (3,226)	$ 7,085
Total other comprehensive income (loss), tax expense (benefit)	(4,031)	(1,289)	2,710
Other comprehensive (loss) income, net of tax	(6,369)	(1,937)	4,375
Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	(10,119)	(571)	12,520
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	(3,913)	(220)	4,789
Other comprehensive income (loss), before reclassifications, net of tax	(6,206)	(351)	7,731
Reclassification from AOCI, pre-tax	(1,186)	(96)	(375)
Reclassification from AOCI, tax expense (benefit)	(459)	(37)	(143)
Reclassification from AOCI, net of tax	(727)	(59)	(232)
Total other comprehensive income (loss), pre-tax	(11,404)	(845)	11,892
Total other comprehensive income (loss), tax expense (benefit)	(4,410)	(325)	4,549
Other comprehensive (loss) income, net of tax	(6,994)	(520)	7,343
Amortization of unrealized holding gains on securities transferred to the held to maturity category
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	(99)	(178)	(253)
Reclassification from AOCI, tax expense (benefit)	(38)	(68)	(97)
Reclassification from AOCI, net of tax	(61)	(110)	(156)
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	856	(420)	(2,627)
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	329	(171)	(1,005)
Other comprehensive income (loss), before reclassifications, net of tax	527	(249)	(1,622)
Total other comprehensive income (loss), pre-tax	856	(420)	(2,627)
Total other comprehensive income (loss), tax expense (benefit)	329	(171)	(1,005)
Other comprehensive (loss) income, net of tax	527	(249)	(1,622)
Defined benefit Pension and Post-Retirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	(383)	432
Reclassification from AOCI, tax expense (benefit)	(148)	165
Reclassification from AOCI, net of tax	(235)	267
Total other comprehensive income (loss), pre-tax	148	(1,961)	(2,180)
Total other comprehensive income (loss), tax expense (benefit)	50	(793)	(834)
Other comprehensive (loss) income, net of tax	98	(1,168)	(1,346)
Net gain (losses) arising during the period
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before reclassifications, pre-tax	51	(2,393)	(2,476)
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	20	(958)	(947)
Other comprehensive income (loss), before reclassifications, net of tax	31	$ (1,435)	(1,529)
Amortization of net actuarial loss recognized in net periodic pension cost
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from AOCI, pre-tax	480		296
Reclassification from AOCI, tax expense (benefit)	178		113
Reclassification from AOCI, net of tax	$ 302		$ 183