TREASURY STOCK (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2017	Mar. 31, 2016
Treasury Stock [Line Items]
Treasury Stock, Value, Acquired, Cost Method					$ 1,028,524	$ 3,089,055	$ 750,378
Repurchase of common shares to satisfy employee withholding tax obligations related to stock-based compensation (in shares)					127,107	65,849	77,761
Repurchase of common shares to satisfy employee withholding tax obligations related to stock-based compensation					$ 167,000	$ 81,900	$ 103,100
Treasury stock, shares	13,190,929				13,190,929	12,427,945
Repurchase Program (Q12016)
Treasury Stock [Line Items]
Stock repurchase program, authorized amount									$ 3,000,000
Treasury Stock, Shares, Acquired					635,877
Treasury Stock, Value, Acquired, Cost Method					$ 861,500
Treasury Stock Repurchased but unsettled by period end	10,215
Treasury Stock Repurchased but unsettled by period end, amount	$ 15,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 2,100,000				$ 2,100,000
Repurchase Program (Q12017) | Subsequent Event
Treasury Stock [Line Items]
Stock repurchase program, authorized amount								$ 2,000,000
Repurchase Program (Q12015)
Treasury Stock [Line Items]
Stock repurchase program, authorized amount		$ 3,000,000
Treasury Stock, Shares, Acquired						2,468,259
Treasury Stock, Value, Acquired, Cost Method						$ 3,000,000
Repurchase Program (Q22013)
Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired		5,813	438,897	114,645
Treasury Stock, Value, Acquired, Cost Method		$ 7,200	$ 500,000	$ 147,300