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	$ 40,867	$ 20,130	$ 98,775	$ 22,138
Securities available for sale:
Unrealized holding gains (losses) on securities	3,702	2,603	(11,241)	19,297
Reclassification adjustment for gains realized in net income	0	(23)	(1,012)	(23)
Total securities available for sale	3,702	2,580	(12,253)	19,274
Derivative instruments:
Unrealized holding (losses) gains on derivative instruments	(4,648)	(793)	6,336	(3,796)
Total derivative instruments	(4,648)	(793)	6,336	(3,796)
Defined benefit pension and post-retirement benefit plans:
Amortization of net actuarial loss recognized in net periodic pension cost	57	51	99	97
Total defined benefit pension and post-retirement benefit plans	57	51	99	97
Other comprehensive (loss) income, net of tax	(889)	1,838	(5,818)	15,575
Comprehensive income	$ 39,978	$ 21,968	$ 92,957	$ 37,713