Segments (Schedule Of Revenues And Long-Lived Assets By Geographical Area) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Revenues, net	$ 186,932	$ 134,213	$ 504,917	$ 379,431
United States [Member]
Segment Reporting Information [Line Items]
Revenues, net	101,350	92,793	291,157	256,863
Long-lived assets (excluding goodwill)	151,320		151,320		113,030
United Kingdom [Member]
Segment Reporting Information [Line Items]
Revenues, net	37,942	17,054	113,734	54,872
Long-lived assets (excluding goodwill)	$ 213,541		$ 213,541		$ 225,212