CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 24,348	$ 19,670	$ 47,331	$ 36,969
Change in securities available-for-sale:
Unrealized holding gain (loss) on securities available-for-sale arising during the period	9,052	2,840	(6,245)	16,059
Reclassification adjustment for gains included in net income	(44)	(49)	(797)	(49)
Net securities gain (loss) activity during the period	9,008	2,791	(7,042)	16,010
Tax effect	(1,892)	(586)	1,479	(3,361)
Net of tax amount	7,116	2,205	(5,563)	12,649
Defined benefit pension plans:
Amortization of net actuarial loss	60	63	120	126
Net gain activity during the period	60	63	120	126
Tax effect	(15)	(16)	(30)	(32)
Net of tax amount	45	47	90	94
Total other comprehensive income (loss), net of tax	7,161	2,252	(5,473)	12,743
Comprehensive income	$ 31,509	$ 21,922	$ 41,858	$ 49,712