SEGMENT AND GEOGRAPHIC INFORMATION (Total Revenue by Major Geographic Area) (Details) (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]
Total revenue, net	$ 214,432		$ 210,084	$ 210,170	$ 196,185	$ 203,523		$ 202,185	$ 193,329	$ 181,041	$ 830,871		$ 780,078		$ 732,068
Total long-lived assets	188,257					144,511					188,257		144,511
United States
Segment Reporting Information [Line Items]
Total revenue, net											642,830	[1]	589,946	[1]	561,307	[1]
Total long-lived assets	166,508	[1]				125,880	[1]				166,508	[1]	125,880	[1]
Europe
Segment Reporting Information [Line Items]
Total revenue, net											90,920		97,184		89,044
Total long-lived assets	20,242					17,274					20,242		17,274
Rest of World
Segment Reporting Information [Line Items]
Total revenue, net											97,121		92,948		81,717
Total long-lived assets	$ 1,507					$ 1,357					$ 1,507		$ 1,357

[1] Includes long-lived assets in Puerto Rico.