SHARE-BASED COMPENSATION (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Weighted average grant date fair value
Share based compensation costs expense	$ 13,132	$ 15,343
Liability for cash-settled restricted stock units	5,711		$ 21,731
Restricted Stock Units (RSUs)
Weighted average grant date fair value
Tax benefits associated with share-based compensation expense	1,889	2,341
Fair value of restricted stock units vested	45,565	$ 47,816
Unrecognized share-based compensation expense	$ 111,909		120,735
Expected weighted average period associated with the recognition of unrecognized share-based compensation expense	2 years 9 months 18 days	2 years 10 months 24 days
Restricted Stock Units (RSUs) | Cash Settled
Weighted average grant date fair value
Liability for cash-settled restricted stock units	$ 5,711		$ 7,878
Performance Vesting Restricted Stock Units | Share Settled
Number of restricted stock units
Nonvested restricted stock units - beginning of period (in shares)	258
Granted (in shares)	97
Vested (in shares)	(27)
Forfeited (in shares)	0
Nonvested restricted stock units - end of period (in shares)	328
Weighted average grant date fair value
Nonvested restricted stock units - beginning of period (in usd per share)	$ 53.31
Granted (in usd per share)	62.26
Vested (in usd per share)	64.01
Forfeited (in usd per share)	0
Nonvested restricted stock units - end of period (in usd per share)	$ 55.09
Performance Vesting Restricted Stock Units | Cash Settled
Number of restricted stock units
Nonvested restricted stock units - beginning of period (in shares)	6
Granted (in shares)	0
Vested (in shares)	(6)
Forfeited (in shares)	0
Nonvested restricted stock units - end of period (in shares)	0
Service Based Restricted Stock Units | Share Settled
Number of restricted stock units
Nonvested restricted stock units - beginning of period (in shares)	1,273
Granted (in shares)	749
Vested (in shares)	(463)
Forfeited (in shares)	(15)
Nonvested restricted stock units - end of period (in shares)	1,544
Weighted average grant date fair value
Nonvested restricted stock units - beginning of period (in usd per share)	$ 54.32
Granted (in usd per share)	62.15
Vested (in usd per share)	55.13
Forfeited (in usd per share)	56.35
Nonvested restricted stock units - end of period (in usd per share)	$ 57.86
Service Based Restricted Stock Units | Cash Settled
Number of restricted stock units
Nonvested restricted stock units - beginning of period (in shares)	853
Granted (in shares)	1
Vested (in shares)	(311)
Forfeited (in shares)	(11)
Nonvested restricted stock units - end of period (in shares)	532