Long-term Debt - Schedule of Actual Ratios and Required Ratios Under Financial Covenants (Details) - Senior Credit Facility	3 Months Ended
	Mar. 31, 2018
Debt Instrument [Line Items]
Interest coverage ratio, as defined under the Senior Credit Facility	10.65
Leverage ratio, as defined under the Senior Credit Facility	2.57
Minimum
Debt Instrument [Line Items]
Required coverage ratio	3.00
Maximum
Debt Instrument [Line Items]
Required leverage ratio	3.75