Ownership, Description of Business, and Summary of Significant Accounting Policies - New Accounting Pronouncements and Changes in Accounting Principles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Jan. 01, 2021	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Investment in receivable portfolios, carrying value	$ 3,291,918		$ 3,283,984	$ 3,137,893	$ 2,890,613
Deferred court costs, net	0		100,172
Other liabilities	146,893		147,436
Accumulated earnings	$ 1,055,668		888,058
Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in receivable portfolios, carrying value			44,166
Deferred court costs, net			(100,172)
Other liabilities			(11,768)
Accumulated earnings		$ 16,100	(44,238)
Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in receivable portfolios, carrying value			3,328,150
Deferred court costs, net			0
Other liabilities			135,668
Accumulated earnings			$ 843,820