Segment Reporting (Schedule of Net Revenues Earned on Major Geographical Areas) (Details) (USD $)	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
Net revenues	$ 356,878,000	$ 334,214,000	$ 358,857,000	$ 366,613,000	$ 401,599,000	$ 340,388,000	$ 328,009,000	$ 312,030,000	$ 1,416,562,000	$ 1,382,026,000	$ 1,090,636,000
United States [Member]
Net revenues									1,361,899,000.0	1,340,727,000	1,069,066,000.0
Canada [Member]
Net revenues									23,422,000.0	10,739,000
United Kingdom [Member]
Net revenues									21,945,000.0	20,479,000	13,527,000.0
Other European [Member]
Net revenues									$ 9,296,000.0	$ 10,081,000	$ 8,043,000.0