Notes Payable - Schedule of Senior Notes (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Long-Term Debt [Line Items]
Long-term debt, gross	$ 2,047,250
Deferred financing costs	(42,012)	$ (43,342)
Total	1,980,232	1,986,980
Current maturities	35,700	35,700
Long-term debt, excluding current maturities	1,944,532	1,951,280
10.875% Notes due 2024
Long-Term Debt [Line Items]
Long-term debt, gross	350,000	350,000
Unamortized deferred financing costs	(16,852)	(17,238)
Deferred financing costs	(6,138)	(6,282)
Total	327,010	326,480
Current maturities	0	0
Long-term debt, excluding current maturities	$ 327,010	$ 326,480