Fair Value Measurements - Financial Instruments Not Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Carrying Amount
Financial Assets
Investment in receivable portfolios, net	$ 3,320,544	$ 3,088,261
Carrying Amount | Global senior secured revolving credit facility
Financial Liabilities
Debt instrument, fair value disclosure	863,707	661,738
Carrying Amount | Cabot securitisation senior facility
Financial Liabilities
Debt instrument, fair value disclosure	408,680	423,522
Carrying Amount | Encore private placement notes
Financial Liabilities
Debt instrument, fair value disclosure	39,080	68,390
Carrying Amount | Senior secured notes
Financial Liabilities
Debt instrument, fair value disclosure	1,476,097	1,480,258
Carrying Amount | 2023 Exchangeable Notes
Financial Liabilities
Debt instrument, fair value disclosure	0	172,500
Carrying Amount | 2025 Convertible Notes
Financial Liabilities
Debt instrument, fair value disclosure	100,000	100,000
Carrying Amount | 2029 Convertible Notes
Financial Liabilities
Debt instrument, fair value disclosure	230,000	0
Estimated Fair Value
Financial Assets
Investment in receivable portfolios, net	3,451,720	3,242,506
Estimated Fair Value | Global senior secured revolving credit facility
Financial Liabilities
Debt instrument, fair value disclosure	863,707	661,738
Estimated Fair Value | Cabot securitisation senior facility
Financial Liabilities
Debt instrument, fair value disclosure	408,680	423,522
Estimated Fair Value | Encore private placement notes
Financial Liabilities
Debt instrument, fair value disclosure	38,212	66,947
Estimated Fair Value | Senior secured notes
Financial Liabilities
Debt instrument, fair value disclosure	1,385,506	1,334,686
Estimated Fair Value | 2023 Exchangeable Notes
Financial Liabilities
Debt instrument, fair value disclosure	0	205,227
Estimated Fair Value | 2025 Convertible Notes
Financial Liabilities
Debt instrument, fair value disclosure	130,269	130,556
Estimated Fair Value | 2029 Convertible Notes
Financial Liabilities
Debt instrument, fair value disclosure	$ 223,256	$ 0