Finance Receivables (Contractual Maturities Of Finance Receivables) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
2018	$ 2,144,991
2019	1,212,136
2020	1,307,617
2021	1,311,778
2022	1,165,976
Thereafter	15,059
Total finance receivables	7,157,557	$ 7,008,801	$ 7,015,331	$ 6,560,245	$ 6,110,256
United States
Accounts, Notes, Loans and Financing Receivable [Line Items]
2018	2,018,646
2019	1,160,372
2020	1,251,444
2021	1,250,821
2022	1,144,281
Thereafter	15,059
Total finance receivables	6,840,623
Canada
Accounts, Notes, Loans and Financing Receivable [Line Items]
2018	126,345
2019	51,764
2020	56,173
2021	60,957
2022	21,695
Thereafter	0
Total finance receivables	$ 316,934