Components of Accumulated Other Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gain on marketable securities	$ 192	$ 67
Tax effect	(74)	(27)
Unrealized gain on marketable securities, net of tax	118	40
Unrealized loss on derivative financial instruments	(1,534)	(1,754)
Tax effect	600	687
Unrealized loss on derivative financial instruments, net of tax	(934)	(1,067)
Foreign currency translation adjustment	892	485
Total accumulated other comprehensive income	$ 76	$ (542)