Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss)
Beginning balance	$ 5,096,384	$ 4,659,670	$ 5,084,066	$ 4,592,120
Other comprehensive (loss) gain before reclassification	(52,292)		(90,966)
Amounts reclassified from other comprehensive (loss) income	53		561
Other comprehensive (loss) income, net	(52,239)	(730)	(90,405)	(10,017)
Ending balance	6,204,913	4,737,807	6,204,913	4,737,807
Total Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(56,098)	(17,005)	(17,932)	(7,718)
Ending balance	(108,337)	$ (17,735)	(108,337)	$ (17,735)
Unrealized Gains and Losses on Available for Sale (AFS) Securities
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(29,716)		9,186
Other comprehensive (loss) gain before reclassification	(52,269)		(91,161)
Amounts reclassified from other comprehensive (loss) income	0		(10)
Other comprehensive (loss) income, net	(52,269)		(91,171)
Ending balance	(81,985)		(81,985)
Unrealized Gains and Losses on Derivatives
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(728)		(1,332)
Other comprehensive (loss) gain before reclassification	(23)		195
Amounts reclassified from other comprehensive (loss) income	(80)		306
Other comprehensive (loss) income, net	(103)		501
Ending balance	(831)		(831)
Defined Benefit Pension Plan
Accumulated Other Comprehensive Income (Loss)
Beginning balance	(25,654)		(25,786)
Other comprehensive (loss) gain before reclassification	0		0
Amounts reclassified from other comprehensive (loss) income	133		265
Other comprehensive (loss) income, net	133		265
Ending balance	$ (25,521)		$ (25,521)