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	$ 473,840	$ 390,606	$ 309,793
Unrealized gains and losses on debt securities available for sale
Net (losses) gains arising during the period	(23,613)	27,845	39,262
Less reclassification adjustment for net (gains) losses included in net income	(491)	(377)	119
Total	(24,104)	27,468	39,381
Unrealized gains and losses on derivatives (cash flow hedges)
Net gains (losses) on derivatives arising during the period	127	(2,251)	(989)
Less reclassification adjustment for net losses included in net income	2,447	2,074	1,291
Total	2,574	(177)	302
Defined benefit pension plan
Net gains (losses) arising during the period	10,306	(3,418)	(2,561)
Amortization of prior service credit	(96)	(98)	(93)
Amortization of actuarial net loss	1,106	721	188
Total	11,316	(2,795)	(2,466)
Other comprehensive (loss) income, net	(10,214)	24,496	37,217
Total comprehensive income	$ 463,626	$ 415,102	$ 347,010