CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 18,322	$ 18,814	$ 51,263	$ 53,582
Other comprehensive income (loss), net of tax:
Net change in fair value of available for sale debt securities	(3,505)	2,886	7,493	19,940
Net change in fair value of cash flow hedges	154	(171)	(888)	(1,235)
Net change in defined benefit plan obligations	410	227	1,229	680
Total other comprehensive income (loss), net of tax	(2,941)	2,942	7,834	19,385
Total comprehensive income	$ 15,381	$ 21,756	$ 59,097	$ 72,967