Condensed Consolidated Statement of Equity - USD ($)	Total	At the Market Program [Member]	Stockholders' Equity, Total [Member]		Stockholders' Equity, Total [Member] At the Market Program [Member]	Common Stock [Member]	Common Stock [Member] At the Market Program [Member]	Preferred Stock [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] At the Market Program [Member]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]		Dividends/Distributions in Excess of Earnings [Member]
Balance, shares Period Start at Dec. 31, 2015						333,771,660
Balance, value Period Start at Dec. 31, 2015			$ 7,089,221,000			$ 3,338,000		$ 98,000	$ 9,548,580,000		$ (4,398,000)		$ (2,458,397,000)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2015								9,775,000
Stock-based compensation related activity, net of forfeitures, value			47,040,000			$ 2,000			47,038,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						246,936
Purchases and retirement of capital stock, value			(24,460,000)			$ (3,000)			(24,457,000)		0		0
Stock Issued During Period, Shares, New Issues							3,828,064
Proceeds from Issuance of Common Stock	$ 323,798,000				$ 323,798,000		$ 38,000			$ 323,760,000
Purchases and retirement of capital stock, shares						(284,282)
Other comprehensive income (loss)	392,000		392,000	[1]		$ 0			0		392,000	[1]	0
Common stock dividends/distributions			(599,588,000)										(599,588,000)
Preferred stock dividends	(21,994,000)		(21,994,000)										(21,994,000)
Net income (loss)	133,898,000		133,898,000			$ 0			0		0		133,898,000
Balance, shares Period End at Jun. 30, 2016						337,562,378
Balance, value Period End at Jun. 30, 2016			6,948,307,000			$ 3,375,000		$ 98,000	9,894,921,000		(4,006,000)		(2,946,081,000)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2016								9,775,000
Balance, shares Period Start at Mar. 31, 2016						337,559,718
Balance, value Period Start at Mar. 31, 2016			7,152,994,000			$ 3,375,000		$ 98,000	9,874,862,000		(4,977,000)		(2,720,364,000)
Preferred Stock, Shares Outstanding Period Start at Mar. 31, 2016								9,775,000
Stock-based compensation related activity, net of forfeitures, value			20,165,000			$ 0			20,165,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						3,826
Purchases and retirement of capital stock, value			(106,000)			$ 0			(106,000)		0		0
Purchases and retirement of capital stock, shares						(1,166)
Other comprehensive income (loss)	971,000		971,000	[1]		$ 0			0		971,000	[1]	0
Common stock dividends/distributions			(300,778,000)										(300,778,000)
Preferred stock dividends	(10,997,000)		(10,997,000)										(10,997,000)
Net income (loss)	$ 86,058,000		86,058,000			$ 0			0		0		86,058,000
Balance, shares Period End at Jun. 30, 2016						337,562,378
Balance, value Period End at Jun. 30, 2016			6,948,307,000			$ 3,375,000		$ 98,000	9,894,921,000		(4,006,000)		(2,946,081,000)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2016								9,775,000
Balance, shares Period Start at Dec. 31, 2016	360,536,659					360,536,659
Balance, value Period Start at Dec. 31, 2016	$ 7,557,115,000		7,557,115,000			$ 3,605,000		$ 0	10,938,236,000		(5,888,000)		(3,378,838,000)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2016	0							0
Stock-based compensation related activity, net of forfeitures, value			53,409,000			$ 8,000			53,401,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						839,402
Purchases and retirement of capital stock, value			(22,594,000)			$ (3,000)			(22,591,000)		0		0
Stock Issued During Period, Shares, New Issues						4,992,300	242,300
Proceeds from Issuance of Common Stock	$ 464,023,000	$ 22,009,000	464,023,000			$ 51,000			463,972,000
Purchases and retirement of capital stock, shares						(252,561)
Other comprehensive income (loss)	705,000		705,000	[1]		$ 0			0		705,000	[1]	0
Common stock dividends/distributions			(693,601,000)										(693,601,000)
Preferred stock dividends	0		0										0
Net income (loss)	$ 231,252,000		231,252,000			$ 0			0		0		231,252,000
Balance, shares Period End at Jun. 30, 2017	366,115,800					366,115,800
Balance, value Period End at Jun. 30, 2017	$ 7,590,309,000		7,590,309,000			$ 3,661,000		$ 0	11,433,018,000		(5,183,000)		(3,841,187,000)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2017	0							0
Balance, shares Period Start at Mar. 31, 2017						361,355,043
Balance, value Period Start at Mar. 31, 2017			7,363,480,000			$ 3,614,000		$ 0	10,968,564,000		(5,713,000)		(3,602,985,000)
Preferred Stock, Shares Outstanding Period Start at Mar. 31, 2017								0
Stock-based compensation related activity, net of forfeitures, value			23,005,000			$ 0			23,005,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						16,710
Purchases and retirement of capital stock, value			(589,000)			$ 0			(589,000)		0		0
Stock Issued During Period, Shares, New Issues						4,750,000
Proceeds from Issuance of Common Stock			442,085,000			$ 47,000			442,038,000
Purchases and retirement of capital stock, shares						(5,953)
Other comprehensive income (loss)	$ 530,000		530,000	[1]		$ 0			0		530,000	[1]	0
Common stock dividends/distributions			(350,316,000)										(350,316,000)
Preferred stock dividends	0
Net income (loss)	$ 112,114,000		112,114,000			$ 0			0		0		112,114,000
Balance, shares Period End at Jun. 30, 2017	366,115,800					366,115,800
Balance, value Period End at Jun. 30, 2017	$ 7,590,309,000		$ 7,590,309,000			$ 3,661,000		$ 0	$ 11,433,018,000		$ (5,183,000)		$ (3,841,187,000)
Preferred Stock, Shares Outstanding Period End at Jun. 30, 2017	0							0

[1] See the condensed statement of operations and other comprehensive income (loss) for the components of "other comprehensive income (loss)."