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	$ 126,051	$ 63,077	$ 49,370
Change in securities available-for-sale (AFS):
Unrealized holding gains (losses) on available-for-sale securities arising during the period	(21,967)	14,431	8,754
Reclassification adjustment for (gains) losses realized in income	(2,218)	(1,464)	(24)
Net unrealized gains (losses)	(24,185)	12,967	8,730
Income tax effect	(5,079)	2,723	1,834
Net of tax amount	(19,106)	10,244	6,896
Change in cash flow hedge derivatives:
Unrealized holding gains (losses) on balance sheet swap	3,025	14,431	8,754
Reclassification adjustment for cash flow hedge derivative (gains) losses included in income	(2,172)		(24)
Net unrealized gains (losses)	853	14,431	8,730
Income tax effect	(179)	(2,723)	(1,834)
Net of tax amount	674	11,708	6,896
Change in unrealized gain/(loss) on postretirement benefit:
Net gain (loss) on defined benefit postretirement medical plan realized during the period	13	195	(310)
Net amortization and deferral	(13)	13	14
Net gain (loss) activity during the period	0	208	(296)
Income tax effect		(43)	143
Net of tax amount	0	165	(153)
Total other comprehensive income (loss)	(18,432)	10,409	6,743
Comprehensive income	$ 107,619	$ 73,486	$ 56,113