Derivative and Hedging Activities - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative [Line Items]
Interest income	$ 281,886,000	$ 235,915,000	$ 792,225,000	$ 714,930,000
Derivative Liabilities	0		0
Gain (losses) on interest rate derivatives designated as cash flow hedge			6,000,000.0
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	23,100,000		23,100,000
Interest Rate Swap | Cash Flow Hedging
Derivative [Line Items]
Derivative, notional amount	2,250,000,000		2,250,000,000		$ 800,000,000
Designated as Hedging Instrument
Derivative [Line Items]
Derivative, notional amount	2,000,000,000.0		2,000,000,000.0		$ 2,000,000,000.0
Interest income	11,000,000.0	$ 1,100,000	22,900,000	$ 684,000
Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Derivative, notional amount	2,000,000,000.0		2,000,000,000.0
LCH | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Derivative, notional amount	$ 4,300,000,000		$ 4,300,000,000