Basis and Summary of Significant Accounting Policies - Components of Prepaid Expenses and Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Prepaid Expenses	$ 39,023	$ 31,509
Prepaid Insurance	33,444	36,735
Assets Held for Sale	9,698	10,118
Deferred Tax Asset	7,556	11,589
Other Assets	29,511	26,548
Prepaid Expenses and Other Assets	$ 119,232	$ 116,499