Condensed Consolidated Statements of Changes in Equity - USD ($) shares in Thousands, $ in Thousands	Common Units	Class B Units	Non-controlling Interest	Total
Balance, Equity at Dec. 31, 2013	$ 3,476,295	$ 602,025	$ 719,813	$ 4,798,133
Balance, Equity (in units) at Dec. 31, 2013	157,766	15,964
Increase (Decrease) in Equity
Issuance of units in public offering, net of offering costs	$ 1,054,195			1,054,195
Issuance of units in public offering, net of offering costs (in units)	16,057
Conversion of Class B units to common units	$ 150,506	$ (150,506)
Conversion of Class B units to common units (in shares)	3,991	(3,991)
Distributions paid	$ (434,654)		(930)	(435,584)
Redeemable non-controlling interest classified as temporary equity			173,210	173,210
Elimination of non-controlling interest from deconsolidation of a subsidiary			(6,592)	(6,592)
Share-based compensation activity	$ 5,042			5,042
Share-based compensation activity (in units)	211
Deferred income tax impact from changes in equity	$ (30,058)			(30,058)
Net (loss) income	98,903		16,109	115,012
Balance, Equity at Sep. 30, 2014	$ 4,320,229	$ 451,519	901,610	5,673,358
Balance, Equity (in units) at Sep. 30, 2014	178,025	11,973
Balance, Temporary Equity at Dec. 31, 2013				235,617
Redeemable Non-controlling Interest (Temporary Equity)
Redeemable non-controlling interest classified as temporary equity				(173,210)
Balance, Temporary Equity at Sep. 30, 2014				62,407
Balance, Equity at Dec. 31, 2014	$ 4,758,243	$ 451,519	983,477	6,193,239
Balance, Equity (in units) at Dec. 31, 2014	186,553	11,973
Increase (Decrease) in Equity
Issuance of units in public offering, net of offering costs	$ 237,929			237,929
Issuance of units in public offering, net of offering costs (in units)	4,451
Conversion of Class B units to common units	$ 150,506	$ (150,506)
Conversion of Class B units to common units (in shares)	3,991	(3,991)
Distributions paid	$ (516,032)		(51,028)	(567,060)
Contributions from non-controlling interest			30,712	30,712
Sale of equity interest in a joint venture			11,319	11,319
Transfer of interest due to sale of joint venture	4,370		(4,370)
Share-based compensation activity	$ 8,741			8,741
Share-based compensation activity (in units)	200
Deferred income tax impact from changes in equity	$ (6,098)			(6,098)
Net (loss) income	(81,442)		49,777	(31,665)
Balance, Equity at Sep. 30, 2015	$ 4,556,217	$ 301,013	$ 1,019,887	$ 5,877,117
Balance, Equity (in units) at Sep. 30, 2015	195,195	7,982