Senior Debt (Details)	3 Months Ended		6 Months Ended
	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2019 USD ($)
Senior Debt (Table Details) [Abstract]
Document Period End Date			Jun. 30, 2019
Unamortized Debt Issuance Expense		$ 2,600,000	$ 1,400,000
Letters of credit, amount outstanding			$ 92,000,000
Line of credit commitment fee percentage			0.40%
Line of credit commitment fee			$ 600,000
Debt refinancing charges		500,000
Debt arrangement and amendment fees		$ 2,100,000
Senior note redemption price	$ 551,019,061.81
Senior note redemption price, percent	100.00%
Financial Covenants Ratios (Table Details) [Abstract]
Required consolidated senior secured leverage ratio, minimum	2.00
Required proforma fixed charge coverage ratio, minimum	1.10
Required minimum consolidated fixed charge coverage ratio	1.10
Minimum [Member]
Senior Debt (Table Details) [Abstract]
Line of credit commitment fee percentage	0.25%		0.30%
Maximum [Member]
Senior Debt (Table Details) [Abstract]
Line of credit commitment fee percentage	0.375%		0.50%
Eurodollar [Member]
Senior Debt (Table Details) [Abstract]
Description of variable rate basis			Eurodollar rate
Prime Rate [Member]
Senior Debt (Table Details) [Abstract]
Description of variable rate basis			prime
Revolving credit facility [Member]
Senior Debt (Table Details) [Abstract]
Senior credit facility, maximum amount	$ 300,000,000		$ 200,000,000
Revolving facility, amount outstanding			$ 0
Maturity date			Dec. 31, 2019
Revolving credit facility [Member] | Eurodollar [Member]
Senior Debt (Table Details) [Abstract]
Margin on Eurodollar rate, actual			1.75%
Revolving credit facility [Member] | Eurodollar [Member] | Minimum [Member]
Senior Debt (Table Details) [Abstract]
Basis margin on variable rate	1.50%		1.50%
Revolving credit facility [Member] | Eurodollar [Member] | Maximum [Member]
Senior Debt (Table Details) [Abstract]
Basis margin on variable rate	2.00%		3.00%
Revolving credit facility [Member] | Prime Rate [Member]
Senior Debt (Table Details) [Abstract]
Margin on Prime Rate, actual			0.75%
Revolving credit facility [Member] | Prime Rate [Member] | Minimum [Member]
Senior Debt (Table Details) [Abstract]
Basis margin on variable rate			0.50%
Revolving credit facility [Member] | Prime Rate [Member] | Maximum [Member]
Senior Debt (Table Details) [Abstract]
Basis margin on variable rate			2.00%
Senior secured term loan [Member]
Senior Debt (Table Details) [Abstract]
Senior credit facility, maximum amount	$ 200,000,000
Senior secured term loan [Member] | Eurodollar [Member]
Senior Debt (Table Details) [Abstract]
Basis margin on variable rate	4.50%