Changes in Equity (Rollforward) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Balances	$ 4,189,612	$ 3,921,241
Dividends declared	(54,917)	(52,585)
Noncontrolling investors, net	(9,905)	(7,504)
Share repurchases		(106,529)
Equity-based compensation	4,273	9,429
Net income	438,755	190,836
Other comprehensive loss, net of tax	3,765	37
Balances	4,571,583	3,954,925
Common Stock
Balances	648	646
Balances	648	646
Treasury Stock
Balances	(1,623,747)	(1,525,113)
Share repurchases		(106,529)
Equity-based compensation	8,881	6,834
Balances	(1,614,866)	(1,624,808)
Additional Paid-In Capital
Balances	1,207,392	1,181,012
Equity-based compensation	(4,447)	2,764
Balances	1,202,945	1,183,776
Retained Earnings
Balances	4,758,969	4,419,296
Dividends declared	(54,917)	(52,585)
Equity-based compensation	(161)	(169)
Net income	430,507	187,340
Balances	5,134,398	4,553,882
Accumulated Other Comprehensive Income (Loss)
Balances	1,902	(7)
Other comprehensive loss, net of tax	3,765	37
Balances	5,667	30
Noncontrolling Interests
Balances	(155,552)	(154,593)
Noncontrolling investors, net	(9,905)	(7,504)
Net income	8,248	3,496
Balances	(157,209)	(158,601)
Redeemable Noncontrolling Interest
Balances	158,614	143,614
Noncontrolling investors, net	5,000	7,400
Balances	$ 163,614	$ 151,014