Long-Term Debt - Financial Covenants in Credit Agreements (Details)		12 Months Ended
	Dec. 18, 2015 USD ($)	Dec. 31, 2019 USD ($)
Debt Disclosure [Abstract]
Total leverage ratio, actual		2.4
Debt service coverage ratio, actual		5.8
Minimum liquidity balance, actual		$ 176,400,000
Total Leverage Ratio		3.50
Debt Service Coverage Ratio		2.00
Minimum liquidity balance	$ 25,000,000	$ 25,000,000