Long-Term Debt - Term Loan Facility (Details) - USD ($)			3 Months Ended	6 Months Ended	18 Months Ended
	Jun. 30, 2018	Jan. 24, 2017	Jun. 30, 2019	Jun. 30, 2019	Jul. 24, 2018	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term Debt			$ 533,682,000	$ 533,682,000			$ 543,697,000
Debt Instrument, Covenant, Tax Sharing Agreement, Distributions Percentage of Net Revenues, Maximum		1.00%
Debt Instrument, Covenant, Repurchase of Capital Stock, Maximum		$ 1,000,000
Debt Instrument, Covenant, Additional Capital Lease Obligation and Purchase Money Indebtedness Maximum		40,000,000
Debt Instrument, Covenant, Additional Other Indebtedness, Maximum		$ 10,000,000
Notes Payable to Banks [Member] | Term Loan Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant, Equity Contribution			12,000,000	12,000,000
Notes Payable to Banks [Member] | Term Loan Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant, Equity Contribution			14,000,000	14,000,000
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Covenant, Maximum First Lien Leverage Ratio		500.00%
Debt Instrument, Covenant, Minimum Interest Coverage Ratio		200.00%
Debt Instrument, Covenant, Maximum Consolidated Capital Expenditure		$ 11,000,000
Allowed Add Back of Pro Forma EBITDA, First Quarter		108,400,000
Allowed Add Back of Pro Forma EBITDA, Second Quarter		77,500,000
Allowed Add Back of Pro Forma EBITDA, Third Quarter		$ 39,400,000
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility, Term A Loan [Member]
Debt Instrument [Line Items]
Long-term Debt			$ 60,400,000	$ 60,400,000			$ 64,800,000
Stated percentage			7.52%	7.52%			768.00%
Commitment fee percent, after closing date					5.00%
Debt Instrument, Repayment Percent of Principal						2.50%
Debt Instrument, Periodic Payment, Principal, First Year	$ 1,800,000
Debt Instrument, Periodic Payment, Principal, Second Year and Thereafter				$ 2,600,000
Repayments of Debt			$ 4,400,000
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility, Term A Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		5.00%
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility, Term A Loan [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		4.00%
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility, Term B Loan [Member]
Debt Instrument [Line Items]
Long-term Debt			$ 439,100,000	$ 439,100,000			$ 440,800,000
Stated percentage			10.77%	10.77%			10.96%
Debt Instrument, Repayment Percent of Principal			1.00%	1.00%
Repayments of Debt			$ 2,300,000
Debt Instrument, Periodic Payment, Principal				$ 1,100,000
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility, Term B Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		8.25%
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility, Term B Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument [Line Items]
Stated percentage		1.00%
Montreign Operating [Member] | Notes Payable to Banks [Member] | Term Loan Facility, Term B Loan [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate		7.25%