INCOME TAXES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Disclosure [Abstract]
Income taxes	$ 37,577	$ 34,007	$ 63,579	$ 57,843
Pre-tax income	114,866	106,534	197,292	197,213
Effective income tax rate (as a percent)			32.20%	29.30%
Unrecognized tax benefits	21,907		21,907
Unrecognized tax benefits that, if recognized, would be reflected as a component of income tax expense	11,920		11,920
Reasonably possible reduction in prior years' unrecognized tax benefits during the next twelve months	(3,930)		(3,930)
Possible increase in Canadian federal and provincial tax due to reassessment	58,651		58,651
Possible interest on Canadian tax reassessment	15,974		15,974
Tax deposit	$ 83,880		$ 83,880
Interest percentage charged on tax assessment	5.00%		5.00%
Rate of interest to be earned on tax deposit upon favorable outcome	1.00%		1.00%