Consolidated Statements Of Changes In Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Mandatory Convertible Preferred Stock [Member]	Retained Earnings [Member]	Non-Controlling Interests - Non-Redeemable [Member]	Total Equity (Permanent) [Member]	Non-controlling Interests - Redeemable (Temporary Equity) [Member]
Balance at Dec. 31, 2014		$ 885,393	$ 166,632	$ 627,522	$ 418,684	$ 2,098,231	$ 184,099
Balance (in shares) at Dec. 31, 2014		48,113,000	1,725,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 159,502			54,713	33,117	87,830	71,672
Issuance of restricted common stock (in shares)		314,000
Cancellation of restricted common stock (in shares)		(7,000)
Stock options exercised		$ 2,080				2,080
Stock options exercised (in shares)		90,000
Stock repurchased	$ (3,700)	$ (3,684)				(3,684)
Stock repurchased (in shares)	(67,000)	(67,000)
Share-based compensation		$ 7,592				7,592
Tax benefit related to exercise of share-based awards		3,533				3,533
Dividends paid on preferred stock				(4,528)		(4,528)
Acquisitions and other transactions impacting noncontrolling interests		599			59,888	60,487	(408)
Distributions to noncontrolling interests, net of capital contributions					(30,989)	(30,989)	(69,819)
Disposals and other transactions impacting noncontrolling interests		(2,194)			2,229	35	(367)
Balance at Jun. 30, 2015		$ 893,319	$ 166,632	677,707	482,929	2,220,587	185,177
Balance (in shares) at Jun. 30, 2015		48,443,000	1,725,000
Balance at Dec. 31, 2015	$ 2,764,747	$ 1,345,418	$ 166,632	781,413	471,284	2,764,747	175,732
Balance (in shares) at Dec. 31, 2015		54,294,000	1,725,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 187,823			76,932	36,046	112,978	74,845
Issuance of restricted common stock (in shares)		587,000
Cancellation of restricted common stock (in shares)		(7,000)
Stock options exercised		$ 450				450
Stock options exercised (in shares)	19,718	20,000
Stock repurchased	$ (5,700)	$ (5,688)				(5,688)
Stock repurchased (in shares)	(77,780)	(78,000)
Share-based compensation		$ 15,068				15,068
Tax benefit related to exercise of share-based awards		3,734				3,734
Dividends paid on preferred stock				(4,528)		(4,528)
Acquisitions and other transactions impacting noncontrolling interests		780			13,584	14,364	4,013
Distributions to noncontrolling interests, net of capital contributions					(38,149)	(38,149)	(77,158)
Disposals and other transactions impacting noncontrolling interests		(2,933)			92	(2,841)	413
Balance at Jun. 30, 2016	$ 2,860,135	$ 1,356,829	$ 166,632	$ 853,817	$ 482,857	$ 2,860,135	$ 177,845
Balance (in shares) at Jun. 30, 2016		54,816,000	1,725,000