CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 18,814	$ 17,511	$ 53,582	$ 51,396
Other comprehensive income (loss), net of tax:
Net change in fair value of available for sale debt securities	2,886	(4,531)	19,940	(18,057)
Net change in fair value of cash flow hedges	(171)	155	(1,235)	1,409
Net change in defined benefit plan obligations	227	361	680	1,081
Total other comprehensive income (loss), net of tax	2,942	(4,015)	19,385	(15,567)
Total comprehensive income	$ 21,756	$ 13,496	$ 72,967	$ 35,829