Revenue and Long-Lived Assets by Geographic Location (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Net service revenues	$ 1,083,864	$ 1,075,119	$ 1,063,228	$ 1,023,684	$ 1,034,213	$ 1,033,173	$ 1,028,383	$ 1,015,444	$ 4,245,895	$ 4,111,213	$ 3,776,976
Assets, long-lived	112,644				107,680				112,644	107,680	107,972
Domestic
Segment Reporting Information [Line Items]
Net service revenues									3,219,820	3,022,274	2,655,443
Assets, long-lived	92,252				86,239				92,252	86,239	87,146
Foreign
Segment Reporting Information [Line Items]
Net service revenues									1,026,075	1,088,939	1,121,533
Assets, long-lived	$ 20,392				$ 21,441				$ 20,392	$ 21,441	$ 20,826