Debt Obligations - Borrowings under Credit Facility and Applicable Interest Rates (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Debt Disclosure [Abstract]
Maximum amount outstanding	$ 517,883	$ 1,462,069	$ 576,993	$ 2,023,326
Average daily amount outstanding	$ 416,089	$ 1,255,171	$ 360,609	$ 1,395,207
Weighted-average interest rate	2.13%	1.57%	2.05%	2.13%

The average effective interest rate during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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