CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Series D Preferred Stock	Series E Preferred Stock	Series F Preferred Stock	Total Stockholders’ Equity	Total Stockholders’ Equity Series D Preferred Stock	Total Stockholders’ Equity Series E Preferred Stock	Total Stockholders’ Equity Series F Preferred Stock	Preferred Stock Series D Preferred Stock	Preferred Stock Series E Preferred Stock	Preferred Stock Series F Preferred Stock	Common Stock	Capital in Excess of Par Value	Capital in Excess of Par Value Series D Preferred Stock	Capital in Excess of Par Value Series E Preferred Stock	Retained Earnings (Loss)	Retained Earnings (Loss) Series D Preferred Stock	Retained Earnings (Loss) Series E Preferred Stock	Retained Earnings (Loss) Series F Preferred Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance at Dec. 31, 2016	$ 3,916,928				$ 3,916,799				$ 287,500	$ 287,500	$ 345,000	$ 1,473	$ 3,322,771			$ (319,254)				$ (8,191)	$ 129
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	265,371				264,973											264,973					398
Dividends declared and paid:
Preferred stock dividends declared and paid		$ (3,598)	$ (16,387)	$ (17,940)		$ (3,598)	$ (16,387)	$ (17,940)									$ (3,598)	$ (16,387)	$ (17,940)
Common stock dividends declared and paid	(268,293)				(268,293)							2	8,825			(277,120)
Redemption of depositary shares		$ (287,500)				$ (287,500)			(287,500)					$ 9,855			$ (9,855)
Issuance of common stock:
Director compensation	1,176				1,176							1	1,175
Stock purchase plan	563				563								563
ATM equity program	247,604				247,604							58	247,546
Restricted shares - net of forfeitures and repurchases	(231)				(231)							3	(234)
Stock issuance costs	(3,782)				(3,782)								(3,782)
Amortization of deferred compensation	12,630				12,630								12,630
Amortization of interest rate hedges	1,932				1,932															1,932
Fair value of forward starting swaps	(7,688)				(7,688)															(7,688)
Valuation adjustments – available-for-sale securities	209				209															209
Realized gain – available-for-sale securities	0
Distributions to noncontrolling interests	(84)																				(84)
Noncontrolling interests	0				126								126								(126)
Ending balance at Dec. 31, 2017	3,840,910				3,840,593				0	287,500	345,000	1,537	3,599,475			(379,181)				(13,738)	317
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	292,485				292,447											292,447					38
Dividends declared and paid:
Preferred stock dividends declared and paid			(16,387)	(17,940)			(16,387)	(17,940)										(16,387)	(17,940)
Common stock dividends declared and paid	(290,201)				(290,201)							3	12,960			(303,164)
Issuance of common stock:
Director compensation	1,375				1,375								1,375
Stock purchase plan	426				426								426
ATM equity program	332,018				332,018							74	331,944
Restricted shares - net of forfeitures and repurchases	(89)				(89)							2	(91)
Stock issuance costs	(3,947)				(3,947)								(3,947)
Amortization of deferred compensation	7,913				7,913								7,913
Amortization of interest rate hedges	3,664				3,664															3,664
Fair value of forward starting swaps	4,080				4,080															4,080
Valuation adjustments – available-for-sale securities	298				298															298
Realized gain – available-for-sale securities	0
Ending balance at Dec. 31, 2018	4,154,605				4,154,250				0	287,500	345,000	1,616	3,950,055			(424,225)				(5,696)	355
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	299,608				299,180											299,180					428
Dividends declared and paid:
Preferred stock dividends declared and paid			(13,201)	$ (17,940)			(13,201)	$ (17,940)										(13,201)	$ (17,940)
Common stock dividends declared and paid	(314,619)				(314,619)							4	19,069			(333,692)
Redemption of depositary shares			$ (287,500)				$ (287,500)			$ (287,500)					$ 9,856			$ (9,856)
Issuance of common stock:
Director compensation	1,294				1,294								1,294
Stock purchase plan	370				370								370
ATM equity program	127,337				127,337							24	127,313
Equity offering	395,500				395,500							70	395,430
Restricted shares - net of forfeitures and repurchases	0				0							4	(4)
Stock issuance costs	(17,521)				(17,521)								(17,521)
Amortization of deferred compensation	9,452				9,452								9,452
Amortization of interest rate hedges	1,307				1,307															1,307
Fair value of forward starting swaps	(5,524)				(5,524)															(5,524)
Valuation adjustments – available-for-sale securities	116				116															116
Realized gain – available-for-sale securities	(1,331)				(1,331)															(1,331)
Other	505				505															505
Distributions to noncontrolling interests	(776)																				(776)
Ending balance at Dec. 31, 2019	$ 4,331,682				$ 4,331,675				$ 0		$ 345,000	$ 1,718	$ 4,495,314			$ (499,229)				$ (11,128)	$ 7