Derivatives - Notional and Fair Value Amounts of Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Amount	$ 318,000	$ 278,200
Fair Value	13,240	2,647
Bank of America, N.A.
Derivative [Line Items]
Notional Amount	174,900	144,500
Fair Value	8,523	870
Barclays Bank PLC
Derivative [Line Items]
Notional Amount	115,300	28,500
Fair Value	3,348	247
Citigroup Inc.
Derivative [Line Items]
Notional Amount	0	0
Fair Value	0	0
Credit Suisse International
Derivative [Line Items]
Notional Amount	0	16,100
Fair Value	0	55
Societe Generale
Derivative [Line Items]
Notional Amount	27,800	89,100
Fair Value	$ 1,369	$ 1,475