SEGMENT AND GEOGRAPHIC INFORMATION - Revenue by Geographic Region (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 330,399	$ 295,623	$ 267,474
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	202,323	171,176	142,508
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	80,844	71,526	76,286
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	15,511	21,039	19,989
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 31,721	$ 31,882	$ 28,691