Earnings Per Share (Schedule Of Earnings Per Share, Basic And Diluted) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2010		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Earnings Per Share [Abstract]
Net income attributable to controlling interests and available to common stockholders	$ 8,153	[1]	$ 46,885	[1]	$ 8,715	[1]	$ 6,480	[1]	$ 8,028	[2]	$ 20,763	[2]	$ 8,203	[2]	$ 3,965	[2]	$ 70,233	[1]	$ 40,959	[2]	$ 5,277
Less: undistributed earnings allocated to unvested restricted shares																	(2,626)		(1,562)		(180)
Net income available to common stockholders																	67,607		39,397		5,097
Weighted Average Shares Outstanding, Basic																	42,201,491		40,347,194		39,244,057
Earnings Per Share, Basic	$ 0.18	[1]	$ 1.06	[1]	$ 0.20	[1]	$ 0.15	[1]	$ 0.19	[2]	$ 0.49	[2]	$ 0.20	[2]	$ 0.10	[2]	$ 1.60	[1]	$ 0.98	[2]	$ 0.13
Add: Undistributed earnings allocated to restricted shares, Diluted																	2,626		1,562		180
Stock options added to the denominator under the treasury stock method																	685,289		712,187		652,309
Less: Undistributed earnings reallocated to restricted shares																	(2,586)		(1,536)		(177)
Net income available to common stockholders and assumed conversions																	$ 67,647		$ 39,423		$ 5,100
Weighted Average Shares Outstanding, Diluted																	42,886,780		41,059,381		39,896,366
Earnings Per Share, Diluted	$ 0.18	[1]	$ 1.05	[1]	$ 0.20	[1]	$ 0.15	[1]	$ 0.19	[2]	$ 0.49	[2]	$ 0.19	[2]	$ 0.09	[2]	$ 1.58	[1]	$ 0.96	[2]	$ 0.13

[1] Includes $37.0 million of tax benefit recorded in the quarter ended September 30 as a result of a tax reporting change with respect to the Company's U.K. operations.

[2] Includes release of $23.7 million and $3.5 million in previously-recognized valuation allowances related to the Company's United States segment for the quarters ended September 30 and December 31, respectively. Additionally, the quarter ended September 30 includes pre-tax charges of approximately $14.5 million related to certain charges associated with the refinancing of the Company's outstanding debt obligations.