Supplemental Condensed Consolidating Financial Information (Details 3) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended
	Jan. 31, 2013	Mar. 31, 2013	Mar. 31, 2012
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities		$ 85,043	$ 207,913
Cash flows from investing activities:
Restricted cash		25,000	1,003
Capital expenditures		(631,558)	(254,263)
Investment in unconsolidated affiliates		(3,012)
Proceeds from disposal of property, plant and equipment		209	291
Net cash flows used in investing activities		(609,361)	(252,969)
Cash flows from financing activities:
Proceeds from public equity offerings, net		103,937	425,629
Proceeds from Credit Facility			13,700
Payments of Credit Facility			(79,700)
Proceeds from long-term debt		1,000,000
Payments of long-term debt		(501,112)
Payments of premiums on redemption of long-term debt	(31,500)	(31,516)
Payments for debt issue costs and deferred financing costs		(14,046)
Contributions from non-controlling interest		385,219	755
Share-based payment activity		(4,555)	(5,841)
Payment of distributions		(106,793)	(75,372)
Payments of SMR liability		(545)	(497)
Net cash flows provided by financing activities		830,589	278,674
Net increase in cash and cash equivalents		306,271	233,618
Cash and cash equivalents at beginning of year	347,899	347,899	117,016
Cash and cash equivalents at end of period		654,170	350,634
Parent
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities		(44,484)	(27,744)
Cash flows from investing activities:
Capital expenditures		(340)	(68)
Equity investments in consolidated affiliates		(14,828)	(13,230)
Distributions from consolidated affiliates		20,552	16,496
Collections of intercompany notes, net			51,400
Net cash flows used in investing activities		5,384	54,598
Cash flows from financing activities:
Proceeds from public equity offerings, net		103,937	425,629
Proceeds from Credit Facility			13,700
Payments of Credit Facility			(79,700)
Proceeds from long-term debt		1,000,000
Payments of long-term debt		(501,112)
Payments of premiums on redemption of long-term debt		(31,516)
Payments for debt issue costs and deferred financing costs		(14,046)
Share-based payment activity		(5,206)	(8,048)
Payment of distributions		(105,945)	(73,410)
Intercompany advances, net		(310,892)	(35,025)
Net cash flows provided by financing activities		135,220	243,146
Net increase in cash and cash equivalents		96,120	270,000
Cash and cash equivalents at beginning of year	210,015	210,015	22
Cash and cash equivalents at end of period		306,135	270,022
Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities		71,711	149,912
Cash flows from investing activities:
Capital expenditures		(31,398)	(91,090)
Equity investments in consolidated affiliates		(407,300)	(66,356)
Investment in unconsolidated affiliates		(3,012)
Distributions from consolidated affiliates		140,968	2,139
Proceeds from disposal of property, plant and equipment		35	1,505
Net cash flows used in investing activities		(300,707)	(153,802)
Cash flows from financing activities:
Payments related to intercompany financing, net			(51,400)
Contributions from parent and affiliates		14,828	13,230
Share-based payment activity		651	2,207
Payment of distributions		(20,552)	(16,496)
Payments of SMR liability		(545)	(497)
Intercompany advances, net		310,892	35,025
Net cash flows provided by financing activities		305,274	(17,931)
Net increase in cash and cash equivalents		76,278	(21,821)
Cash and cash equivalents at beginning of year	102,979	102,979	99,580
Cash and cash equivalents at end of period		179,257	77,759
Non-Guarantor Subsidiaries
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities		51,091	88,402
Cash flows from investing activities:
Restricted cash		25,000	1,003
Capital expenditures		(592,643)	(166,976)
Proceeds from disposal of property, plant and equipment		174
Net cash flows used in investing activities		(567,469)	(165,973)
Cash flows from financing activities:
Payments related to intercompany financing, net		(452)
Contributions from parent and affiliates		407,300	66,356
Contributions from non-controlling interest		385,219	755
Payment of distributions		(141,816)	(4,101)
Net cash flows provided by financing activities		650,251	63,010
Net increase in cash and cash equivalents		133,873	(14,561)
Cash and cash equivalents at beginning of year	34,905	34,905	17,414
Cash and cash equivalents at end of period		168,778	2,853
Consolidating Adjustments
Condensed Consolidating Statements of Cash Flows
Net cash (used in) provided by operating activities		6,725	(2,657)
Cash flows from investing activities:
Capital expenditures		(7,177)	3,871
Equity investments in consolidated affiliates		422,128	79,586
Distributions from consolidated affiliates		(161,520)	(18,635)
Collections of intercompany notes, net			(51,400)
Proceeds from disposal of property, plant and equipment			(1,214)
Net cash flows used in investing activities		253,431	12,208
Cash flows from financing activities:
Payments related to intercompany financing, net		452	51,400
Contributions from parent and affiliates		(422,128)	(79,586)
Payment of distributions		161,520	18,635
Net cash flows provided by financing activities		$ (260,156)	$ (9,551)