STOCK-BASED COMPENSATION - Equity Awards (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Compensation cost charged against income
Operating expenses			$ 32,719	$ 28,552	$ 28,764
Total employee and non-employee share-based compensation expense included in income, before income tax			32,719	28,552	28,764
Less: Amount of income tax benefit recognized in earnings			9,058	2,932	7,730
Amount charged against net income			23,661	25,620	21,034
Operating expense
Compensation cost charged against income
Total employee and non-employee share-based compensation expense included in income, before income tax			$ 32,700	$ 28,600	$ 28,800
Stock options
Stock-based compensation
Weighted-average grant-date fair value of options granted (in dollars per share)			$ 50.20	$ 31.49	$ 22.57
Total intrinsic value of options exercised			$ 870,100	$ 47,100	$ 91,600
Cash received from option exercises			49,200	$ 17,200	$ 21,300
Total unrecognized compensation expense related to non-vested shares granted to employees			$ 69,100
Cost expected to be recognized over a weighted-average period			2 years 8 months 12 days
Stock units expected to vest (in shares)			6,238
Restricted stock units
Stock-based compensation
Total unrecognized compensation expense related to non-vested shares granted to employees			$ 11,900
Cost expected to be recognized over a weighted-average period			1 year 9 months 18 days
Stock units expected to vest (in shares)			200
Number of Shares
Non-vested at the beginning of the period (in shares)		149	149
Granted (in shares)	8	83
Vested (in shares)			(48)
Forfeited/cancelled (in shares)			(14)
Non-vested at the end of the period (in shares)			178	149
Weighted Average Grant-Date Fair Value
Non-vested at the beginning of the period (in dollars per share)		$ 61.09	$ 61.09
Granted (in dollars per share)	$ 147.36	$ 135.48	136.50	$ 84.38	$ 53.50
Vested (in dollars per share)			59.32
Forfeited/cancelled (in dollars per share)			63.57
Non-vested at the end of the period (in dollars per share)			$ 99.58	$ 61.09
Incentive stock option
Compensation cost charged against income
Total employee and non-employee share-based compensation expense included in income, before income tax			$ 6,200	$ 4,800	$ 5,200
Non-Qualified stock option
Compensation cost charged against income
Total employee and non-employee share-based compensation expense included in income, before income tax			$ 26,500	$ 23,800	$ 23,600