Related Party Transactions (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Rent expense		$ 21,697,000	$ 25,318,000	$ 21,620,000
Rivers And Lakes Group [Member]
Related Party Transaction [Line Items]
Rent expense		0	0	95,000
NASDI And Yankee [Member]
Related Party Transaction [Line Items]
Rent and property taxes			375,000	449,000
Lease termination fees	$ 490,000
Rent expense		0
Terra Contracting L L C
Related Party Transaction [Line Items]
Rent expense		243,000	243,000	243,000
Magnus Real Estate Group L L C
Related Party Transaction [Line Items]
Rent expense		$ 402,000	$ 46,000	$ 0