CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 12,962	$ 12,327	$ 37,943	$ 34,319
Other comprehensive income (loss), net of tax:
Net change in fair value of securities available for sale	1,094	(91)	3,323	1,651
Net change in fair value of cash flow hedges	(13)	(4)	(364)	(94)
Net change in defined benefit plan obligations	217	166	427	497
Total other comprehensive income (loss), net of tax	1,298	71	3,386	2,054
Total comprehensive income	$ 14,260	$ 12,398	$ 41,329	$ 36,373