Basis and Summary of Significant Accounting Policies - Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Accounts Payable	$ 54,663	$ 71,941
Accrued Insurance Costs	44,120	47,649
Accrued Salaries and Benefits	40,628	41,612
Accrued Real Estate and Sales Taxes	29,521	32,986
Deferred Rent	31,193	31,859
Other Accrued Expenses and Liabilities	81,795	71,719
Accounts Payable and Accrued Expenses	$ 281,920	$ 297,766