Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Series H Preferred Stock [Member]	Common Stock [Member]	Additional paid-in capital [Member]	Distributions in excess of accumulated earnings [Member]	Accumulated other comprehensive loss, net [Member]	Noncontrolling Interest [Member]
Balances at Dec. 31, 2013	$ 1,998,238	$ 73,750	$ 4	$ 2,345,763	$ (474,426)	$ (60,472)	$ 113,619
Balances (in shares) at Dec. 31, 2013		2,950	37,421
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	134,438				122,150		12,288
Reversal of unrealized gains upon the sale of marketable securities	(886)					(841)	(45)
Change in fair value of derivatives and amortization of swap settlements	4,168					3,721	447
Changes in fair value of marketable securities, net	6,302					6,140	162
Issuance of common stock under:
Stock consideration in the Merger, net	3,774,087		$ 2	3,774,085
Stock consideration in the Merger, net (in shares)			23,067
Stock option and restricted stock plans, net	11,024			11,024
Stock option and restricted stock plans, net (in shares)			218
Equity distribution agreements, net	532,670			532,670
Equity distribution agreements, net (in shares)			2,943
Equity-based compensation costs	11,872			5,719			6,153
Reclassification of noncontrolling interest to redeemable noncontrolling interest	(20,890)			(19,823)			(1,067)
Changes in the redemption value of redeemable noncontrolling interest	312			312
Conversion of Series G preferred stock	4,349			4,349
Conversion of Series G preferred stock (in shares)			34
Contributions from noncontrolling interest	1,419,816						1,419,816
Retirement of noncontrolling interest	(1,419,816)						(1,419,816)
Distributions to noncontrolling interest	(17,069)						(17,069)
Redemptions of noncontrolling interest	(4,026)			(2,934)			(1,092)
Common and preferred stock dividends	(298,521)				(298,521)
Balances at Dec. 31, 2014	6,136,068	$ 73,750	$ 6	6,651,165	(650,797)	(51,452)	113,396
Balances (in shares) at Dec. 31, 2014		2,950	63,683
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	248,239				232,120		16,119
Reversal of unrealized gains upon the sale of marketable securities	0
Change in fair value of derivatives and amortization of swap settlements	7,893					7,637	256
Changes in fair value of marketable securities, net	1,865					1,804	61
Issuance of common stock under:
Stock option and restricted stock plans, net	26,540			26,540
Stock option and restricted stock plans, net (in shares)			207
Equity distribution agreements, net	332,137			332,137
Equity distribution agreements, net (in shares)			1,482
Equity-based compensation costs	9,646			5,946			3,700
Reclassification of noncontrolling interest to redeemable noncontrolling interest	(19,772)			(7,657)			(12,115)
Changes in the redemption value of redeemable noncontrolling interest	(2,615)			(2,615)
Contributions from noncontrolling interest	0
Retirement of noncontrolling interest	0
Distributions to noncontrolling interest	(21,705)						(21,705)
Redemptions of noncontrolling interest	(2,621)			(2,199)			(422)
Redemptions of noncontrolling interest (in shares)			7
Common and preferred stock dividends	(378,652)				(378,652)
Balances at Dec. 31, 2015	6,337,023	$ 73,750	$ 6	7,003,317	(797,329)	(42,011)	99,290
Balances (in shares) at Dec. 31, 2015		2,950	65,379
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	438,410				414,979		23,431
Reversal of unrealized gains upon the sale of marketable securities	(4,848)					(4,689)	(159)
Change in fair value of derivatives and amortization of swap settlements	15,926					15,403	523
Changes in fair value of marketable securities, net	(828)					(801)	(27)
Issuance of common stock under:
Stock option and restricted stock plans, net	18,949			18,949
Stock option and restricted stock plans, net (in shares)			140
Equity distribution agreements, net	(384)			(384)
Equity-based compensation costs	10,899			8,246			2,653
Redemption of Series H preferred stock	(73,750)	$ (73,750)		2,541	(2,541)
Redemption of Series H preferred stock (in shares)		(2,950)
Retirement of common stock, net	(1,045)			(1,045)
Retirement of common stock, net (in shares)			(5)
Changes in the redemption value of redeemable noncontrolling interest	768			172			596
Contributions from noncontrolling interest	0
Retirement of noncontrolling interest	0
Distributions to noncontrolling interest	(25,854)						(25,854)
Redemptions of noncontrolling interest	(2,511)			(2,117)			(394)
Redemptions of noncontrolling interest (in shares)			14
Common and preferred stock dividends	(420,518)				(420,518)
Balances at Dec. 31, 2016	$ 6,292,237	$ 0	$ 6	$ 7,029,679	$ (805,409)	$ (32,098)	$ 100,059
Balances (in shares) at Dec. 31, 2016		0	65,528