Condensed Consolidated Statement of Stockholders' Equity and Partners' Capital (USD $) In Thousands	Total	Partners' Capital [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2013	$ 667,971	$ 666,803				$ 1,168
Net loss	(150,153)				(150,153)
Capital contributions	124,667	124,667
Incentive unit compensation	87	87
Pension obligation adjustment	(1,358)					(1,358)
IPO proceeds	550,025		1,600	548,425
IPO offering costs	(5,303)			(5,303)
Effect of corporate reorganization		(791,557)		847,726	(56,169)
Balance at Sep. 30, 2014	$ 1,185,936		$ 1,600	$ 1,390,848	$ (206,322)	$ (190)