Condensed Consolidating Financial Information - Condensed Consolidating Statement of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 409,873	$ 191,065	$ 199,158
Net cash provided by (used in) investing activities	(1,136,657)	(664,260)	(840,579)
Net cash provided by (used in) financing activities	410,168	765,063	714,612
Net (decrease) increase in cash and cash equivalents	(316,616)	291,868	73,191
Cash and cash equivalents at beginning of period	458,956	167,088	93,897
Cash and cash equivalents at end of period	142,340	458,956	167,088
Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	388,177	182,961	195,734
Net cash provided by (used in) investing activities	(1,108,241)	(661,886)	(838,177)
Net cash provided by (used in) financing activities	410,168	765,063	714,612
Net (decrease) increase in cash and cash equivalents	(309,896)	286,138	72,169
Cash and cash equivalents at beginning of period	451,431	165,293	93,124
Cash and cash equivalents at end of period	141,535	451,431	165,293
Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	21,698	8,104	3,425
Net cash provided by (used in) investing activities	(28,419)	(2,374)	(2,402)
Net cash provided by (used in) financing activities	0	0	0
Net (decrease) increase in cash and cash equivalents	(6,721)	5,730	1,023
Cash and cash equivalents at beginning of period	7,525	1,795	772
Cash and cash equivalents at end of period	804	7,525	1,795
Non-Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(2)	0	(1)
Net cash provided by (used in) investing activities	(18,799)	(33,929)	(103,915)
Net cash provided by (used in) financing activities	18,802	33,929	103,915
Net (decrease) increase in cash and cash equivalents	1	0	(1)
Cash and cash equivalents at beginning of period	0	0	1
Cash and cash equivalents at end of period	1	0	0
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	0	0	0
Net cash provided by (used in) investing activities	18,802	33,929	103,915
Net cash provided by (used in) financing activities	(18,802)	(33,929)	(103,915)
Net (decrease) increase in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0