Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Retained Earnings [Member]	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2018	$ (787,707)	$ 43	$ 4,214	$ 6,117,254	$ 5,333,804	$ 77,249	$ 5,411,053
Balance (in shares) at Dec. 31, 2018		43	421,389
Net income	116,169	$ 0	$ 0	0	116,169	509	116,678
Redeemable noncontrolling interests income	0	0	0	0	0	(92)	(92)
Dividends declared to common and preferred shares	(132,703)	0	0	0	(132,703)	0	(132,703)
Distributions to noncontrolling interests	0	0	0	0	0	(685)	(685)
Issuance of common stock	0	$ 0	$ 8	(8)	0	0	0
Issuance of common stock (in shares)		0	783
Surrender of restricted stock	0	$ 0	$ (2)	(3,250)	(3,252)	0	(3,252)
Surrender of restricted stock (in shares)		0	(187)
Exercise of common stock options	0	$ 0	$ 0	681	681	0	681
Exercise of common stock options (in shares)		0	52
Amortization of equity awards	0	$ 0	$ 0	5,178	5,178	0	5,178
Balance at Mar. 31, 2019	(804,241)	$ 43	$ 4,220	6,119,855	5,319,877	76,981	5,396,858
Balance (in shares) at Mar. 31, 2019		43	422,037
Balance at Dec. 31, 2019	(904,679)	$ 20	$ 4,318	5,765,233	4,864,892	64,015	4,928,907
Balance (in shares) at Dec. 31, 2019		20	431,815
Net income	90,100	$ 0	$ 0	0	90,100	289	90,389
Redeemable noncontrolling interests income	0	0	0	0	0	(262)	(262)
Dividends declared to common and preferred shares	(127,452)	0	0	0	(127,452)	0	(127,452)
Distributions to noncontrolling interests	0	0	0	0	0	(555)	(555)
Issuance of common stock	0	$ 0	$ 9	(9)	0	0	0
Issuance of common stock (in shares)		0	921
Surrender of restricted stock	0	$ 0	$ (3)	(5,156)	(5,159)	0	(5,159)
Surrender of restricted stock (in shares)		0	(274)
Exercise of common stock options	0	$ 0	$ 1	980	981	0	981
Exercise of common stock options (in shares)		0	63
Amortization of equity awards	0	$ 0	$ 0	5,729	5,729	0	5,729
Acquisition of noncontrolling interests	0	0	0	(19,500)	(19,500)	(609)	(20,109)
Balance at Mar. 31, 2020	$ (942,031)	$ 20	$ 4,325	$ 5,747,277	$ 4,809,591	$ 62,878	$ 4,872,469
Balance (in shares) at Mar. 31, 2020		20	432,525