INVESTMENTS - Investments in Continuous Unrealized Loss Position for Less Than Twelve Months (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 46,672	$ 19,265
Unrealized Losses	(51)	(13)
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	17,737	2,494
Unrealized Losses	(6)	(2)
Corporate Bonds and Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	28,935	16,771
Unrealized Losses	$ (45)	$ (11)