Long-term Debt - Receivables Facility (Details) - Receivables Facility [Member] - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 18, 2018	Dec. 31, 2018	Dec. 31, 2017	Mar. 19, 2018
Debt Instrument [Line Items]
Secured debt, Maximum Borrowing Capacity				$ 75.0
Debt cost, 1-month LIBOR plus	1.00%
Debt Instrument, Unused Borrowing Capacity, Fee percentage	0.35%
Receivables facililty, debt aggregate costs		$ 0.1	$ 1.0