Consolidated Statement of Changes in Stockholders' Equity and Noncontrolling Interests - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Redeemable Noncontrolling Interests	Series D Convertible Preferred Stock	Series D Convertible Preferred Stock Preferred Stock	Series D Convertible Preferred Stock Additional Paid-In Capital	Series D Convertible Preferred Stock Retained Earnings	Series E Cumulative Redeemable Preferred Stock	Series E Cumulative Redeemable Preferred Stock Preferred Stock	Series E Cumulative Redeemable Preferred Stock Additional Paid-In Capital	Series E Cumulative Redeemable Preferred Stock Retained Earnings
Common stock dividends declared (per share)	$ 3.45							$ 1.75				$ 0.4031
Preferred stock dividends declared (per share)								$ 1.75				$ 0
Beginning balance at Dec. 31, 2016	$ 5,370,971	$ 877	$ 4,672,650	$ 0	$ 5,355	$ 475,175			$ 86,914				$ 130,000
Beginning balance (shares) at Dec. 31, 2016		87,665,880
Increase (Decrease) in Stockholders' Equity
Net Income	193,146			169,093		24,053
Total other comprehensive income (loss)	44,603				44,669	(66)
Redemption of noncontrolling interests	(541)					(541)
Distributions to noncontrolling interests	(21,505)					(21,505)
Contributions from and sales of noncontrolling interests	52,625		7,747			44,878
Issuance of common stock (in shares)		11,694,101
Issuance of common stock	1,275,397	$ 117	1,275,280
Issuance pursuant to stock plan (in shares)		423,705
Issuance pursuant to stock plan	42,399	$ 4	42,395
Repurchases of 7.00% Series D preferred stock								$ (17,934)	(12,528)	$ 391	$ (5,797)
Conversion/redemption of preferred stock												$ (130,350)	(130,000)	$ 5,132	$ (5,482)
Dividends declared on common stock	(329,485)			(329,485)
Dividends declared on preferred stock	(7,666)			(7,666)				$ (5,200)
Distributions in excess of earnings			(179,337)	179,337
Ending balance (shares) at Dec. 31, 2017		99,783,686
Ending balance at Dec. 31, 2017	$ 6,471,660	$ 998	5,824,258	0	50,024	521,994			74,386				0
Beginning balance at Dec. 31, 2016							$ 11,307
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income							1,058
Distributions to noncontrolling interests							(856)
Ending balance at Dec. 31, 2017							11,509
Common stock dividends declared (per share)	$ 3.73							$ 1.75
Preferred stock dividends declared (per share)								$ 1.75				$ 0
Increase (Decrease) in Stockholders' Equity
Net Income	$ 401,930			379,312		22,618
Total other comprehensive income (loss)	(10,688)				(10,688)
Distributions to noncontrolling interests	(29,810)					(29,810)
Contributions from and sales of noncontrolling interests	27,418		257			27,161
Issuance of common stock (in shares)		10,915,120
Issuance of common stock	1,304,640	$ 109	1,304,531
Issuance pursuant to stock plan (in shares)		313,010
Issuance pursuant to stock plan	45,978	$ 3	45,975
Repurchases of 7.00% Series D preferred stock								$ (13,976)	(10,050)	314	(4,240)
Dividends declared on common stock	(398,914)			(398,914)
Dividends declared on preferred stock	(5,060)			(5,060)				$ (5,100)
Reclassification of net unrealized gains on non-real estate investments upon adoption of new ASU on financial instruments on January 1, 2018	$ 90,750			140,521	(49,771)
Distributions in excess of earnings			111,619	(111,619)
Ending balance (shares) at Dec. 31, 2018	111,011,816	111,011,816
Ending balance at Dec. 31, 2018	$ 7,883,928	$ 1,110	7,286,954	0	(10,435)	541,963			64,336				$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income							863
Redemption of noncontrolling interests							(1,597)
Distributions to noncontrolling interests							(846)
Contributions from and sales of noncontrolling interests							857
Ending balance at Dec. 31, 2018	$ 10,786						10,786
Common stock dividends declared (per share)	$ 4.00							$ 1.3125
Preferred stock dividends declared (per share)								$ 1.3125				$ 0
Increase (Decrease) in Stockholders' Equity
Net Income	$ 403,172			363,165		40,007
Total other comprehensive income (loss)	686				686
Distributions to noncontrolling interests	(47,395)					(47,395)
Contributions from and sales of noncontrolling interests	1,134,939		381,162			753,777
Issuance of common stock (in shares)		8,723,076
Issuance of common stock	1,216,445	$ 87	1,216,358
Issuance pursuant to stock plan (in shares)		666,836
Issuance pursuant to stock plan	67,913	$ 7	67,906
Taxes paid related to net settlement of equity awards (in shares)		179,008
Taxes paid related to net settlement of equity awards	(25,477)	$ (2)	(25,475)
Repurchases of 7.00% Series D preferred stock								$ (9,240)	(6,875)	215	$ (2,580)
Conversion/redemption of preferred stock		$ 6						(100)	(57,461)	$ 57,355
Dividends declared on common stock	(463,964)			(463,964)
Dividends declared on preferred stock	$ (3,204)			(3,204)				$ (3,200)
Distributions in excess of earnings			(110,108)	110,108
Ending balance (shares) at Dec. 31, 2019	120,800,315	120,800,315
Ending balance at Dec. 31, 2019	$ 10,154,178	$ 1,208	$ 8,874,367	$ 0	$ (9,749)	$ 1,288,352			$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income							875
Distributions to noncontrolling interests							(830)
Contributions from and sales of noncontrolling interests							1,469
Ending balance at Dec. 31, 2019	$ 12,300						$ 12,300
Increase (Decrease) in Stockholders' Equity
Conversion of 7.00% Series D preferred stock (in shares)	(578,000)	577,595