Finance Receivables - Contractual Maturities Of Finance Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	$ 1,582,171
2022	1,243,116
2023	1,393,589
2024	1,522,985
2025	1,011,727
Thereafter	80,356
Total financing receivables	6,833,944	$ 7,572,947	$ 7,411,816	$ 7,157,557	$ 7,008,801
United States
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	1,505,981
2022	1,194,078
2023	1,340,552
2024	1,465,470
2025	1,001,327
Thereafter	80,356
Total financing receivables	6,587,764
Canada
Accounts, Notes, Loans and Financing Receivable [Line Items]
2021	76,190
2022	49,038
2023	53,037
2024	57,515
2025	10,400
Thereafter	0
Total financing receivables	$ 246,180