Summary of Significant Accounting Policies - Schedule of Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Before Tax
Unrealized holding (losses)/gains on available-for-sale-securities, before tax	$ 48,226			$ (23,943)			$ (6,596)	$ (47,225)
Other comprehensive income/(loss) before tax	47,671			(38,204)			(47,690)	(86,051)
Provision (Benefit)
Unrealized holding gains/(losses) on available-for-sale securities, provision (benefit)	10,127			(5,028)			(1,386)	(9,917)
Other comprehensive income/(loss), provision (benefit)	10,011			(8,023)			(10,014)	(18,071)
After Tax
Unrealized holding gains/(losses) on available-for-sale securities, after tax	38,099			(18,915)			(5,210)	(37,308)
Reclassification adjustments, after tax	(1,343)			(6,195)			(7,782)	(13,993)
Unrealized gains/(losses) on cash flow hedges	39,003			(23,986)			(29,894)	(53,987)
Other comprehensive income/(loss) net of tax	37,660	$ 29,940	$ (105,276)	(30,181)	$ (34,097)	$ (3,702)	(37,676)	(67,980)
Cash Flow Hedges
Before Tax
Unrealized gain/(losses) on cash flow hedges, before taxes	1,145			(6,419)			(31,246)	(21,113)
Other comprehensive income/(loss) before tax	2,959			(6,736)			(27,429)	(22,373)
Provision (Benefit)
Unrealized gains/(losses) on cash flow hedges, provision (benefit)	241			(1,348)			(6,562)	(4,434)
Other comprehensive income/(loss), provision (benefit)	622			(1,415)			(5,760)	(4,699)
After Tax
Reclassification adjustments, after tax	1,433			(250)			3,015	(995)
Unrealized gains/(losses) on cash flow hedges	904			(5,071)			(24,684)	(16,679)
Other comprehensive income/(loss) net of tax	2,337			(5,321)			(21,669)	(17,674)
Available-for-Sale Securities | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest
Before Tax
Other comprehensive income/(loss) before tax	47,235			(24,925)			(9,554)	(50,272)
Provision (Benefit)
Other comprehensive income/(loss), provision (benefit)	9,919			(5,234)			(2,006)	(10,557)
After Tax
Reclassification adjustments, after tax	(783)			(776)			(2,338)	(2,407)
Unrealized gains/(losses) on cash flow hedges	38,099			(18,915)			(5,210)	(37,308)
Other comprehensive income/(loss) net of tax	37,316			(19,691)			(7,548)	(39,715)
Held-to-Maturity Securities | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest
Before Tax
Other comprehensive income/(loss) before tax	(2,523)			(6,543)			(10,707)	(13,406)
Provision (Benefit)
Other comprehensive income/(loss), provision (benefit)	(530)			(1,374)			(2,248)	(2,815)
After Tax
Reclassification adjustments, after tax	(1,993)			(5,169)			(8,459)	(10,591)
Unrealized gains/(losses) on cash flow hedges	0			0			0	0
Other comprehensive income/(loss) net of tax	(1,993)			(5,169)			(8,459)	(10,591)
Net Interest Income | Available-for-Sale Securities | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest | Reclassification adjustments
Before Tax
Reclassification adjustments, before tax	(976)			(961)			(2,916)	(2,870)
Provision (Benefit)
Reclassification adjustments, provision (benefit)	(205)			(202)			(612)	(603)
After Tax
Reclassification adjustments, after tax	(771)			(759)			(2,304)	(2,267)
Net Interest Income | Held-to-Maturity Securities | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest | Reclassification adjustments
Before Tax
Reclassification adjustments, before tax	(2,523)			(6,543)			(10,707)	(13,406)
Provision (Benefit)
Reclassification adjustments, provision (benefit)	(530)			(1,374)			(2,248)	(2,815)
After Tax
Reclassification adjustments, after tax	(1,993)			(5,169)			(8,459)	(10,591)
Other Income | Available-for-Sale Securities | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest | Reclassification adjustments
Before Tax
Reclassification adjustments, before tax	(15)			(21)			(42)	(177)
Provision (Benefit)
Reclassification adjustments, provision (benefit)	(3)			(4)			(8)	(37)
After Tax
Reclassification adjustments, after tax	(12)			(17)			(34)	(140)
Interest Expense | Cash Flow Hedges | Reclassification adjustments
Before Tax
Reclassification adjustments, before tax	1,814			(317)			3,817	(1,260)
Provision (Benefit)
Reclassification adjustments, provision (benefit)	381			(67)			802	(265)
After Tax
Reclassification adjustments, after tax	$ 1,433			$ (250)			$ 3,015	$ (995)