CAPITAL STOCK (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Feb. 29, 2016	May. 31, 2015	Feb. 28, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Capital Stock [Line Items]
Common stock, shares authorized				200,000,000	200,000,000
Preferred stock, shares authorized				15,000,000	15,000,000
Preferred stock outstanding (in shares)				0
Issuance of common stock		6,900,000
Price per share sold		$ 109.00
Common stock, par value (in dollars per share)		$ 0.01		$ 0.01	$ 0.01
Proceeds from sale of common stock, net of underwriting fees		$ 730,000
Dividends
Cash dividend declared (in dollars per share)	$ 0.08		$ 0.16
Dividend payable
Dividend declared				$ 59,313	$ 55,664	$ 48,423
Dividend per share				$ 0.64	$ 0.64	$ 0.56
Additional Shares Issued [Member]
Capital Stock [Line Items]
Issuance of common stock		900,000