Receivables (Installment Receivables by Class) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Total Installment Receivables
Non-Impaired installment receivables with no related allowance recorded	$ 712	$ 689
Impaired installment receivables with a related allowance recorded	2,350	2,671
Total installment receivables	3,062	3,360
Unpaid Principal Balance
Non-Impaired installment receivables with no related allowance recorded	687	667
Impaired installment receivables with a related allowance recorded	2,350	2,671
Total installment receivables	3,037	3,338
Non-Impaired Financing Receivable, Related Allowance	0	0
Related Allowance for Doubtful Accounts
Impaired installment receivables with a related allowance recorded	1,482	1,542
Interest Income Recognized
Non-Impaired installment receivables with no related allowance recorded	38	127
Impaired installment receivables with a related allowance recorded	0	0
Total installment receivables	38	127
U.S.
Total Installment Receivables
Impaired installment receivables with a related allowance recorded	2,350	2,669
Unpaid Principal Balance
Impaired installment receivables with a related allowance recorded	2,350	2,669
Related Allowance for Doubtful Accounts
Impaired installment receivables with a related allowance recorded	1,482	1,540
Interest Income Recognized
Impaired installment receivables with a related allowance recorded	0	0
CANADA
Total Installment Receivables
Non-Impaired installment receivables with no related allowance recorded	712	689
Impaired installment receivables with a related allowance recorded	0	2
Total installment receivables	712	691
Unpaid Principal Balance
Non-Impaired installment receivables with no related allowance recorded	687	667
Impaired installment receivables with a related allowance recorded	0	2
Total installment receivables	687	669
Non-Impaired Financing Receivable, Related Allowance	0	0
Related Allowance for Doubtful Accounts
Impaired installment receivables with a related allowance recorded	0	2
Interest Income Recognized
Non-Impaired installment receivables with no related allowance recorded	38	127
Impaired installment receivables with a related allowance recorded	0	0
Total installment receivables	$ 38	$ 127

Financing Receivable, Interest Income, Accrual Method

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Financing Receivable, Recorded Investment

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Financing Receivable, with No Related Allowance, Interest Income, Accrual Method

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Financing Receivable, with No Related Allowance, Recorded Investment

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Financing Receivable, with No Related Allowance, Unpaid Principal Balance

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Impaired Financing Receivable, Related Allowance [Abstract]

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Non-Impaired Financing Receivable, Related Allowance

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Amount of allowance for credit losses related to recorded investment.

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Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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