Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 57,908	$ 2,008
Securities available for sale:
Unrealized holding (losses) gains on securities	(14,943)	16,694
Reclassification adjustment for gains realized in net income	(1,012)	0
Total securities available for sale	(15,955)	16,694
Derivative instruments:
Unrealized holding gains (losses) on derivative instruments	10,984	(3,003)
Total derivative instruments	10,984	(3,003)
Defined benefit pension and post-retirement benefit plans:
Amortization of net actuarial loss recognized in net periodic pension cost	42	46
Total defined benefit pension and post-retirement benefit plans	42	46
Other comprehensive (loss) income, net of tax	(4,929)	13,737
Comprehensive income	$ 52,979	$ 15,745