Consolidated Statements Of Changes In Equity (USD $) In Thousands, except Share data, unless otherwise specified	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, 2012		$ 183,867		$ 505,621	$ 310,978	$ 1,000,466	$ 175,382
Balance (in shares) at Dec. 31, 2012		31,941,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	190,376			53,145	36,962	90,107	100,269
Issuance of restricted common stock (in shares)		292,000
Cancellation of restricted common stock (in shares)		(16,000)
Stock options exercised		23,289				23,289
Stock options exercised (in shares)		961,000
Common stock repurchased		(35,481)				(35,481)
Common stock repurchased (in shares)		(1,024,000)
Share-based compensation		6,070				6,070
Tax benefit related to exercise of stock options		4,847				4,847
Distributions to noncontrolling interests, net of capital contributions					(36,301)	(36,301)	(100,504)
Acquisitions and other transactions impacting noncontrolling interests		(223)			38,055	37,832	(316)
Disposals and other transactions impacting noncontrolling interests		(1,545)			2,010	465	504
Balance at Sep. 30, 2013		180,824	0	558,766	351,704	1,091,294	175,335
Balance (in shares) at Sep. 30, 2013		32,154,000	0
Balance at Dec. 31, 2013	1,125,556	185,873	0	578,324	361,359	1,125,556	177,697
Balance (in shares) at Dec. 31, 2013		32,353,000	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	165,709			26,322	40,672	66,994	98,715
Issuance of restricted common stock (in shares)		272,000
Cancellation of restricted common stock (in shares)		(12,000)
Stock options exercised		2,150				2,150
Stock options exercised (in shares)	89,481	89,000
Common stock repurchased		(2,890)				(2,890)
Common stock repurchased (in shares)		(69,000)
Share-based compensation		7,388				7,388
Tax benefit related to exercise of stock options		2,288				2,288
Issuance of common stock		693,401				693,401
Issuance of common stock (in shares)		15,490,000
Issuance of mandatory convertible preferred stock			166,647			166,647
Issuance of mandatory convertible preferred stock (in shares)			1,725,000
Dividends paid on preferred stock				(2,239)		(2,239)
Distributions to noncontrolling interests, net of capital contributions					(40,735)	(40,735)	(98,677)
Acquisitions and other transactions impacting noncontrolling interests		762			42,119	42,881
Disposals and other transactions impacting noncontrolling interests		(3,350)			(520)	(3,870)	(1,219)
Balance at Sep. 30, 2014	$ 2,057,571	$ 885,622	$ 166,647	$ 602,407	$ 402,895	$ 2,057,571	$ 176,516
Balance (in shares) at Sep. 30, 2014		48,123,000	1,725,000