CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 19,281	$ 17,527	$ 30,916	$ 21,778
Unrealized gains and losses:
Unrealized holding gains (losses) on available-for-sale securities arising during the period	4,027	(1,780)	9,585	(6,799)
Tax effect	(1,055)	445	(2,477)	1,737
Net of tax	2,972	(1,335)	7,108	(5,062)
Reclassification adjustment for realized losses included in net income	9		1
Tax effect	(2)
Net of tax	7		1
Unrealized (losses) gains on cash flow hedges	(897)	178	(1,287)	1,094
Tax effect	252	(49)	361	(307)
Net of tax	(645)	129	(926)	787
Unrealized pension plan gains and losses:
Unrealized pension plan (losses) gains before reclassifications			(562)	236
Tax effect			158	(67)
Net of tax			(404)	169
Reclassification adjustment for amortization included in net income	90	92	179	183
Tax effect	(25)	(26)	(50)	(51)
Net of tax	65	66	129	132
Total other comprehensive (loss) income	2,399	(1,140)	5,908	(3,974)
Total comprehensive income	$ 21,680	$ 16,387	$ 36,824	$ 17,804