Long-term Debt - Schedule of Actual Ratios and Required Ratios Under Financial Covenants (Details) - Lenders named therein and Bank of America Merrill Lynch - Senior Credit Facility	6 Months Ended
	Jun. 30, 2017
Minimum
Debt Instrument [Line Items]
Interest coverage ratio, as defined under the Senior Credit Facility	12.40
Leverage ratio, as defined under the Senior Credit Facility	2.12
Maximum
Debt Instrument [Line Items]
Interest coverage ratio, as defined under the Senior Credit Facility	1
Leverage ratio, as defined under the Senior Credit Facility	1