Purchased Receivables - Summary of Components of Net Purchased Receivables (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Jan. 01, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased receivables	$ 11,818		$ 13,995
Total	11,818		13,922
Purchased Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses on purchased receivables	$ 0	$ 0	$ 73	$ 99	$ 94