CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 95,733	$ 84,337	$ 87,047
Change in securities available -for-sale:
Unrealized holding gain (loss) on securities available-for-sale arising during the period	(14,553)	20,148	23,438
Reclassification adjustment for (gains) losses included in net income	(797)	(433)	(142)
Net securities gain (loss) activity during the period	(15,350)	19,715	23,296
Tax effect	3,224	(4,140)	(4,893)
Net of tax amount	(12,126)	15,575	18,403
Defined benefit pension plans:
Net gain (loss) on defined benefit pension plans	390	(105)	(409)
Amortization of net actuarial loss	242	251	205
Net gain (loss) on activity during the period	632	146	(204)
Tax effect	(157)	(36)	51
Net of tax amount	475	110	(153)
Total other comprehensive income (loss), net of tax	(11,651)	15,685	18,250
Comprehensive income	$ 84,082	$ 100,022	$ 105,297