INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income taxes (Note 15)	$ 23,378	$ 22,052
Pre-tax income	$ 84,198	$ 77,900
Effective income tax rate (as a percent)	27.80%	28.30%
Transition Tax Expense Benefit Net Resulting from Tax Reform Act	$ 2,500
Unrecognized tax benefits	16,676
Unrecognized tax benefits that, if recognized, would be reflected as a component of income tax expense	13,080
Reasonably possible reduction in prior years' unrecognized tax benefits during the next twelve months	$ 2,397