OTHER ASSETS AND OTHER LIABILITIES (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended				12 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
OTHER ASSETS AND OTHER LIABILITIES
Face value of debt for which membership interest is exchanged		$ 5,000				$ 14,059
Loss recognized for difference between the book value of the membership interests and the fair value of Note						4,094
Note convertible into membership interest (as a percent)		55.00%
Impairment charges (Included within Other expenses).	2,662		2,700	2,255	5,362	6,349
Other liabilities
Deferred revenues					7,247	16,879
Payroll related liabilities					15,418	16,364
Future purchase commitment and contingent consideration liabilities					3,727	13,681
Deferred tax liabilities					7,943	14,962
Unrecognized tax benefits					8,957	11,187	11,849	10,773
Financial instruments sold, not yet purchased					1,481	976
Other					38,801	23,514
Total Other liabilities					$ 83,574	$ 97,563