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	$ 17,273	$ 17,674	$ 34,768	$ 33,885
Other comprehensive income (loss), net of tax:
Net change in fair value of available for sale debt securities	6,033	(3,112)	17,054	(13,526)
Net change in fair value of cash flow hedges	(622)	365	(1,064)	1,254
Net change in defined benefit plan obligations	226	360	453	720
Total other comprehensive income (loss), net of tax	5,637	(2,387)	16,443	(11,552)
Total comprehensive income	$ 22,910	$ 15,287	$ 51,211	$ 22,333