Long-Term Debt and Revolving Lines of Credit - Financial Covenants in Credit Agreements (Details)		12 Months Ended
	Dec. 18, 2015 USD ($)	Dec. 31, 2016 USD ($)
Debt Disclosure [Abstract]
Total leverage ratio, actual		0.0281
Debt service coverage ratio, actual		0.0423
Total leverage ratio, covenant requirement		3.75
Debt service coverage ratio, covenant requirement		2.00
Minimum liquidity balance, actual		$ 136,000,000
Minimum liquidity balance	$ 25,000,000	$ 25,000,000