Business and Summary of Significant Accounting Policies - Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Prepaid Expenses	$ 31,509	$ 21,769
Prepaid Insurance	36,735	53,716
Assets Held for Sale	10,118	8,866
Deferred Tax Asset	11,589	5,912
Other Assets	26,548	18,881
Prepaid Expense and Other Assets	$ 116,499	$ 109,144