Financing Arrangements - Variable Interest Rates (Details) - JP Morgan - Term Loan Facility	12 Months Ended
	Dec. 31, 2017
Eurodollar
Debt Instrument [Line Items]
Basis spread on variable rate	5.00%
Eurodollar | Moody's, B1 Rating | S&P's, B Plus Rating or Higher
Debt Instrument [Line Items]
Basis spread on variable rate	4.25%
Eurodollar | Moody's, B2 Rating | S&P's, B Rating
Debt Instrument [Line Items]
Basis spread on variable rate	4.75%
Eurodollar | Moody's, B3 Rating | S&P's, B Minus Rating or Lower
Debt Instrument [Line Items]
Basis spread on variable rate	5.50%
ABR Spread
Debt Instrument [Line Items]
Basis spread on variable rate	4.00%
ABR Spread | Moody's, B1 Rating | S&P's, B Plus Rating or Higher
Debt Instrument [Line Items]
Basis spread on variable rate	3.25%
ABR Spread | Moody's, B2 Rating | S&P's, B Rating
Debt Instrument [Line Items]
Basis spread on variable rate	3.75%
ABR Spread | Moody's, B3 Rating | S&P's, B Minus Rating or Lower
Debt Instrument [Line Items]
Basis spread on variable rate	4.50%