Condensed Consolidated Statements of Changes in Partners' Capital and Stockholders' Equity (USD $) In Thousands	Total	Class A Limited Partners	Class B Limited Partners	Class C Limited Partners	Common Stock	Additional Paid-in Capital	Accumulated Deficit During Development Stage
Balance (Inception) at Nov. 10, 2005
Class A limited partners' contributions	$ 1,256,738	$ 1,256,738
Class B & C limited partners' equity compensation	7,718		6,984	734
Common stock issued upon corporate reorganization		(1,256,738)	(6,984)	(734)	2,743	1,261,713
Common stock issued at initial public offering, net of offering costs	807,259				630	806,629
Common stock issued at private placement	42,188				32	42,156
Common stock issued at the closing of the over-allotment portion of initial public offering, net of offering costs	101,256				80	101,176
Common stock issued at public offering, net of costs	967,512				538	966,974
Common stock issued for restricted stock and stock options					44	(44)
Equity based compensation	52,989					52,989
Common stock withheld for taxes on equity based compensation	(361)				(1)	(360)
Exercise of stock options	338					338
Conversion option relating to 2.625% convertible senior notes, net of allocated costs	381,416					381,416
Net income (loss)	(927,835)						(927,835)
Balance at Dec. 31, 2012	2,689,218				4,066	3,612,987	(927,835)
Common stock issued for restricted stock and stock options					1	(1)
Equity based compensation	6,283					6,283
Exercise of stock options	74					74
Net income (loss)	(128,087)						(128,087)
Balance at Mar. 31, 2013	$ 2,567,488				$ 4,067	$ 3,619,343	$ (1,055,922)