Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 3,387,045	$ 1,662,734	$ 3,428,052	$ 1,600,153
Other comprehensive loss before reclassifications			(48,568)	60,497
Less: Amounts reclassified from accumulated other comprehensive income			11,913	4,184
Net change in fair value			(60,481)	56,313
Ending balance	3,430,622	1,693,630	3,430,622	1,693,630
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(26,192)	11,420	54,234	(43,847)
Ending balance	(6,247)	12,466	(6,247)	12,466
Securities available for sale
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			45,672	21,798
Other comprehensive loss before reclassifications	25,429	414	(48,568)	26,701
Less: Amounts reclassified from accumulated other comprehensive income	1	127	908	222
Net change in fair value			(49,476)	26,479
Ending balance	(3,804)	48,277	(3,804)	48,277
Unrealized Gains and (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			29,815	15,624
Other comprehensive loss before reclassifications			0	33,796
Less: Amounts reclassified from accumulated other comprehensive income			11,857	7,366
Net change in fair value			(11,857)	26,430
Ending balance	17,958	42,054	17,958	42,054
Defined benefit pension plans, actuarial loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance			(21,253)	(81,269)
Other comprehensive loss before reclassifications	0	0	0	0
Less: Amounts reclassified from accumulated other comprehensive income			(852)	(3,404)
Net change in fair value			852	3,404
Ending balance	$ (20,401)	$ (77,865)	$ (20,401)	$ (77,865)