CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 24,119	$ 22,776	$ 71,450	$ 59,745
Change in securities available-for-sale:
Unrealized holding gain (loss) on securities available-for-sale arising during the period	(14,411)	789	(20,656)	16,848
Reclassification adjustment for gains included in net income	0	(314)	(797)	(363)
Net securities gain (loss) activity during the period	(14,411)	475	(21,453)	16,485
Tax effect	3,026	(101)	4,505	(3,462)
Net of tax amount	(11,385)	374	(16,948)	13,023
Defined benefit pension plans:
Amortization of net actuarial loss	61	63	181	189
Net gain activity during the period	61	63	181	189
Tax effect	(15)	(15)	(45)	(47)
Net of tax amount	46	48	136	142
Total other comprehensive income (loss), net of tax	(11,339)	422	(16,812)	13,165
Comprehensive income	$ 12,780	$ 23,198	$ 54,638	$ 72,910