Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net change in Unrealized (losses) gains, tax (benefit) expense	$ 1,958	$ 2,870	$ 2,737	$ 9,350
Reclassification adjustment for gains, tax expense	253	207	367	323
Amortization of unrealized gain on securities reclassified to held-to-maturity, tax expense	62	62	121	127
Change in unfunded pension liability related to unrealized (loss) gain, prior service cost and transition obligation, tax (benefit) expense	(15)	(13)	(27)	280
Net change in cash flow hedge, tax expense	$ 161	$ 0	$ 92	$ 0