Financing Receivables - Summary of Financing Receivables by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Customer balances with amounts reclassified to trade accounts receivable that are:
1 to 90 Days Past Due	$ 11,300	$ 6,167
91 to 180 Days Past Due	3,727	550
181 Days Past Due	967	273
Total customer balances with past due amounts reclassified to trade accounts receivable	15,994	6,990
Total customer balances with no past due amounts reclassified to trade accounts receivable	4,709	1,194
Total financing receivables with contractual maturities of one year or less	9,081	5,068
Less allowance for losses	(3,244)	(2,198)	$ (654)
Total financing receivables	$ 26,540	$ 11,054