Consolidated Statements Of Changes In Equity (USD $)	Total	Common Stock Including Additional Paid in Capital [Member]	Retained Earnings [Member]	Non-Controlling Interests - Non-Redeemable [Member]	Total Equity (Permanent) [Member]	Non-controlling Interests - Redeemable [Member]
Balance at Dec. 31, 2011		$ 173,187,000	$ 443,058,000	$ 132,222,000	$ 748,467,000	$ 170,636,000
Balance (in shares) at Dec. 31, 2011		31,284,000
Issuance of restricted common stock (in shares)		281,000
Stock options exercised		6,672,000			6,672,000
Stock options exercised (in shares)		325,000
Stock repurchased	(5,956,000)	(7,219,000)			(7,219,000)
Stock repurchased (in shares)	(216,994)	(266,000)
Share-based compensation, value	3,412,000	3,412,000			3,412,000
Tax Benefit from Stock Options Exercised		594,000			594,000
Net earnings	110,484,000		30,312,000	13,017,000	43,329,000	67,155,000
Distributions to noncontrolling interests, net of capital contributions				(13,709,000)	(13,709,000)	(69,022,000)
Sale of noncontrolling interest, value		(1,587,000)		2,494,000	907,000	0
Acquisitions and other transactions impacting noncontrolling interests				2,223,000	2,223,000	2,467,000
Disposals and other transactions impacting noncontrolling interests		(369,000)			(369,000)	176,000
Balance at Jun. 30, 2012		174,690,000	473,370,000	136,247,000	784,307,000	171,412,000
Balance (in shares) at Jun. 30, 2012		31,624,000
Balance at Dec. 31, 2012	1,000,466,000	183,867,000	505,621,000	310,978,000	1,000,466,000	175,382,000
Balance (in shares) at Dec. 31, 2012		31,941,000
Issuance of restricted common stock (in shares)		292,000
Cancellation of restricted common stock (in shares)		(17,000)
Stock options exercised		13,728,000			13,728,000
Stock options exercised (in shares)	567,213	568,000
Stock repurchased	(23,349,000)	(26,164,000)			(26,164,000)
Stock repurchased (in shares)	(699,659)	(789,000)
Share-based compensation, value	3,966,000	3,966,000			3,966,000
Tax Benefit from Stock Options Exercised		2,968,000			2,968,000
Net earnings	128,109,000		36,374,000	25,450,000	61,824,000	66,285,000
Distributions to noncontrolling interests, net of capital contributions				(24,371,000)	(24,371,000)	(66,879,000)
Purchase of noncontrolling interest, value		(223,000)		(316,000)	(539,000)	(316,000)
Sale of noncontrolling interest, value		(1,471,000)		2,222,000	751,000	628,000
Acquisitions and other transactions impacting noncontrolling interests				11,153,000	11,153,000	0
Disposals and other transactions impacting noncontrolling interests				(317,000)	(317,000)	0
Balance at Jun. 30, 2013	$ 1,043,465,000	$ 176,671,000	$ 541,995,000	$ 324,799,000	$ 1,043,465,000	$ 175,100,000
Balance (in shares) at Jun. 30, 2013		31,995,000