CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 4,251	$ 11,880
Unrealized gains and losses on securities:
Unrealized holding (losses) gains on available-for-sale securities arising during the period	(5,019)	689
Tax effect	1,292	(268)
Net of tax	(3,727)	421
Reclassification adjustment for realized gains included in net income		(1,596)
Tax effect		579
Net of tax		(1,017)
Unrealized gains on cash flow hedge	916	160
Tax effect	(258)	(65)
Net of tax	658	95
Unrealized pension plan gains and losses:
Unrealized pension plan gains (losses) before reclassifications	236	(2)
Tax effect	(67)	1
Net of tax	169	(1)
Reclassification adjustment for realized losses included in net income	91	103
Tax effect	(25)	(42)
Net of tax	66	61
Total other comprehensive loss	(2,834)	(441)
Total comprehensive income	$ 1,417	$ 11,439