Summary of Significant Accounting Policies - Schedule of Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Other comprehensive income/(loss) before taxes:
Other comprehensive income/(loss), Before Tax	$ 83,123	$ (133,260)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income/(loss), Provision (Benefit)	17,456	(27,984)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gains/(losses), After Tax		(100,353)	$ 66,773
Less reclassification adjustments, Provision (Benefit)		(4,923)	(1,106)
Other comprehensive income/(loss), After Tax	65,667	(105,276)	$ 65,667
Securities | Available-for-Sale Securities
Other comprehensive income/(loss) before taxes:
Unrealized gain/(losses), Before Tax	67,356	(98,334)
Other comprehensive income/(loss), Before Tax	66,364	(99,316)
Other Comprehensive Income (Loss), Tax [Abstract]
Unrealized gains/(losses), Provision (Benefit)	14,145	(20,649)
Other comprehensive income/(loss), Provision (Benefit)	13,936	(20,855)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gains/(losses), After Tax	53,211	(77,685)
Other comprehensive income/(loss), After Tax	52,428	(78,461)
Securities | Held-to-Maturity Securities
Other comprehensive income/(loss) before taxes:
Less reclassification adjustments, Before Tax	(2,157)	(5,688)
Other comprehensive income/(loss), Before Tax	(2,157)	(5,688)
Other Comprehensive Income (Loss), Tax [Abstract]
Less reclassification adjustments, Provision (Benefit)	453	1,194
Other comprehensive income/(loss), Provision (Benefit)	(453)	(1,194)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Less reclassification adjustments, Provision (Benefit)	(1,704)	(4,494)
Other comprehensive income/(loss), After Tax	(1,704)	(4,494)
Securities | Net interest income | Available-for-Sale Securities
Other comprehensive income/(loss) before taxes:
Less reclassification adjustments, Before Tax	(984)	(969)
Other Comprehensive Income (Loss), Tax [Abstract]
Less reclassification adjustments, Provision (Benefit)	207	203
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Less reclassification adjustments, Provision (Benefit)	(777)	(766)
Securities | Other income | Available-for-Sale Securities
Other comprehensive income/(loss) before taxes:
Less reclassification adjustments, Before Tax	(8)	(13)
Other Comprehensive Income (Loss), Tax [Abstract]
Less reclassification adjustments, Provision (Benefit)	2	3
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Less reclassification adjustments, Provision (Benefit)	(6)	(10)
Cash flow hedges
Other comprehensive income/(loss) before taxes:
Unrealized gain/(losses), Before Tax	17,170	(28,695)
Less reclassification adjustments, Before Tax	1,746	439
Other comprehensive income/(loss), Before Tax	18,916	(28,256)
Other Comprehensive Income (Loss), Tax [Abstract]
Unrealized gains/(losses), Provision (Benefit)	3,608	(6,027)
Less reclassification adjustments, Provision (Benefit)	365	92
Other comprehensive income/(loss), Provision (Benefit)	3,973	(5,935)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gains/(losses), After Tax	13,562	(22,668)
Less reclassification adjustments, Provision (Benefit)	1,381	347
Other comprehensive income/(loss), After Tax	14,943	(22,321)
AOCI Attributable to Parent
Other comprehensive income/(loss) before taxes:
Other comprehensive income/(loss), Before Tax	83,123	(133,260)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income/(loss), Provision (Benefit)	17,456	(27,984)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive income/(loss), After Tax	$ 65,667	$ (105,276)