Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss)
Beginning balance	$ 5,084,066	$ 4,592,120
Other comprehensive (loss) gain before reclassification	(38,674)
Amounts reclassified from other comprehensive (loss) income	508
Other comprehensive (loss) income, net	(38,166)	(9,287)
Ending balance	5,096,384	4,659,670
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(17,932)	(7,718)
Ending balance	(56,098)	$ (17,005)
Unrealized Gains and Losses on Available for Sale (AFS) Securities
Accumulated Other Comprehensive Income (Loss)
Beginning balance	9,186
Other comprehensive (loss) gain before reclassification	(38,892)
Amounts reclassified from other comprehensive (loss) income	(10)
Other comprehensive (loss) income, net	(38,902)
Ending balance	(29,716)
Unrealized Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(1,332)
Other comprehensive (loss) gain before reclassification	218
Amounts reclassified from other comprehensive (loss) income	386
Other comprehensive (loss) income, net	604
Ending balance	(728)
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(25,786)
Other comprehensive (loss) gain before reclassification	0
Amounts reclassified from other comprehensive (loss) income	132
Other comprehensive (loss) income, net	132
Ending balance	$ (25,654)