Consolidated Statements Of Changes In Equity (USD $)	Total	Common Stock	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interest Nonredeemable Member [Member]	Total Equity [Member]	Non-Controlling Interests - Redeemable (Temporary Equity) [Member]
Balance at Dec. 31, 2010		$ 171,522,000	$ 393,061,000	$ (515,000)	$ 12,799,000	$ 576,867,000	$ 147,740,000
Balance (in shares) at Dec. 31, 2010		31,040,000
Issuance of restricted common stock (in shares)		277,000
Cancellation of restricted common stock		(525,000)				(525,000)
Cancellation of restricted common stock (in shares)		(23,000)
Stock options exercised		4,628,000				4,628,000
Stock options exercised (in shares)		236,000
Stock repurchased	(6,185,000)	(6,185,000)				(6,185,000)
Stock repurchased (in shares)	(248,100)	(248,000)
Share-based compensation expense	3,171,000	3,171,000				3,171,000
Tax benefit related to exercise of stock options		143,000				143,000
Net earnings (loss)	91,005,000		23,323,000		3,202,000	26,525,000	64,480,000
Distributions to noncontrolling interests, net of capital contributions					(2,740,000)	(2,740,000)	(64,580,000)
Purchase of noncontrolling interest, value		15,000				15,000
Sale of noncontrolling interest, value		(1,427,000)				(1,427,000)	1,318,000
Acquisitions and other transactions impacting noncontrolling interests					10,536,000	10,536,000	16,730,000
Gain on interest rate swap, net of income tax expense				515,000		515,000
Balance at Jun. 30, 2011		171,342,000	416,384,000	0	23,797,000	611,523,000	165,688,000
Balance (in shares) at Jun. 30, 2011		31,282,000
Balance at Dec. 31, 2011	748,467,000	173,187,000	443,058,000	0	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)	324,860	325,000
Stock repurchased	(5,956,000)	(7,219,000)				(7,219,000)
Stock repurchased (in shares)	(216,994)	(266,000)
Share-based compensation expense	3,412,000	3,412,000				3,412,000
Tax benefit related to exercise of stock options		594,000				594,000
Net earnings (loss)	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
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	$ 784,307,000	$ 174,690,000	$ 473,370,000	$ 0	$ 136,247,000	$ 784,307,000	$ 171,412,000
Balance (in shares) at Jun. 30, 2012		31,624,000