Derivative Instruments and Hedging Activities - Cash Flow Hedges (Details) - Cash Flow Hedging - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Mar. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross notional amount outstanding			$ 2,035,000	$ 1,905,000
Derivative asset fair value in other assets	[1]		6,053	727
Derivative liability fair value in other liabilities	[1]		$ 198	$ 119
Weighted-average interest rate received			0.96%	1.88%
Weighted-average interest rate paid			0.77%	1.74%
Weighted-average maturity (in years)		1 year 2 months 4 days	2 years 3 months 18 days

[1] Certain cash flow hedges are transacted through a clearinghouse ("centrally cleared") and their change in fair value is settled by the counterparties to the transaction, which results in no fair value.