SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES, STOCK BASED COMPENSATION EXPENSE (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Stock-Based Compensation Expense [Abstract]
Compensation expense	$ 7,879,000	$ 17,326,000
Net cash proceeds from the exercise of stock options and ESPP	3,001,000	6,807,000
Excess tax benefits realized from stock option exercised and restricted stock awards vested	23,429,000	7,305,000
Exercise of stock options (in shares)	43,416	146,530
Cost of Revenues [Member]
Stock-Based Compensation Expense [Abstract]
Compensation expense	1,208,000	1,401,000
Selling and Marketing [Member]
Stock-Based Compensation Expense [Abstract]
Compensation expense	1,101,000	1,808,000
Software Development [Member]
Stock-Based Compensation Expense [Abstract]
Compensation expense	1,447,000	2,431,000
General and Administrative [Member]
Stock-Based Compensation Expense [Abstract]
Compensation expense	4,123,000	11,686,000
Performance-Based Restricted Common Stock [Member]
Stock-Based Compensation Expense [Abstract]
Cumulative EBITDA required for award shares to vest	90,000,000
Number of consecutive quarters to mantain cumulative EBITDA required for award shares to vest	4
Compensation expense	$ 2,200,000	$ 11,300,000