INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income taxes (Note 12)	$ 24,531	$ 20,257	$ 69,218	$ 54,264
Pre-tax income	130,642	$ 80,296	$ 292,508	$ 199,236
Effective income tax rate (as a percent)			23.70%	27.20%
Unrecognized tax benefits	16,006		$ 16,006
Unrecognized tax benefits that, if recognized, would be reflected as a component of income tax expense	11,876		11,876
Reasonably possible reduction in prior years' unrecognized tax benefits during the next twelve months	$ 1,379		$ 1,379