STOCK-BASED COMPENSATION - Equity Awards (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Compensation cost charged against income
Operating expenses				$ 52,282	$ 45,848	$ 32,719
Total employee and non-employee share-based compensation expense included in income, before income tax				52,282	45,848	32,719
Less: Amount of income tax benefit recognized in earnings				(100,635)	(34,909)	(9,058)
Amount charged against net income				(48,353)	10,939	23,661
Operating expense
Compensation cost charged against income
Total employee and non-employee share-based compensation expense included in income, before income tax				$ 52,300	$ 45,800	$ 32,700
Stock options
Stock-based compensation
Weighted-average grant-date fair value of options granted (in dollars per share)				$ 18.29	$ 16.90	$ 16.73
Total intrinsic value of options exercised				$ 285,800	$ 70,600	$ 870,100
Cash received from option exercises				52,600	$ 16,400	$ 49,200
Total unrecognized compensation expense related to non-vested shares granted to employees	$ 83,400			$ 83,400
Cost expected to be recognized over a weighted-average period				2 years 7 months 6 days
Stock units expected to vest (in shares)	16,863			16,863
Restricted stock units
Stock-based compensation
Total unrecognized compensation expense related to non-vested shares granted to employees	$ 14,200			$ 14,200
Cost expected to be recognized over a weighted-average period				1 year 6 months
Stock units expected to vest (in shares)	500			500
Number of Shares
Non-vested at the beginning of the period (in shares)			556	556
Granted (in shares)	2	23	252
Vested (in shares)				(300)
Forfeited/cancelled (in shares)				(3)
Non-vested at the end of the period (in shares)	530			530	556
Weighted Average Grant-Date Fair Value
Non-vested at the beginning of the period (in dollars per share)			$ 39.95	$ 39.95
Granted (in dollars per share)	$ 59.43	$ 50.86	$ 46.27	46.74	$ 44.71	$ 45.50
Vested (in dollars per share)				37.26
Forfeited/cancelled (in dollars per share)				27.02
Non-vested at the end of the period (in dollars per share)	$ 45.09			$ 45.09	$ 39.95
Incentive stock option
Compensation cost charged against income
Total employee and non-employee share-based compensation expense included in income, before income tax				$ 8,700	$ 8,000	$ 6,200
Non-Qualified stock option
Compensation cost charged against income
Total employee and non-employee share-based compensation expense included in income, before income tax				$ 43,600	$ 37,800	$ 26,500