Segments (Schedule of Revenues and Long-Lived Assets by Geographical Area) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Revenues, net	$ 202,617	$ 186,932	$ 171,820	$ 146,165	$ 140,160	$ 134,213	$ 134,213	$ 111,005	$ 707,534	$ 519,591	$ 433,841
Long-lived assets (excluding goodwill)	599,907				464,165				599,907	464,165	263,469
United States [Member]
Segment Reporting Information [Line Items]
Revenues, net									399,573	348,065	286,922
Long-lived assets (excluding goodwill)	152,175				112,630				152,175	112,630
United Kingdom [Member]
Segment Reporting Information [Line Items]
Revenues, net									153,305	80,778	77,349
Long-lived assets (excluding goodwill)	225,050				230,580				225,050	230,580
Czech Republic [Member]
Segment Reporting Information [Line Items]
Revenues, net										54,542	52,871
Long-lived assets (excluding goodwill)					47,081					47,081
Brazil [Member]
Segment Reporting Information [Line Items]
Long-lived assets (excluding goodwill)	$ 81,934								$ 81,934