PREFERRED STOCK - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
	Sep. 15, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Class of Stock [Line Items]
Gain on repurchase of mandatory convertible preferred stock		$ 1,280	$ 0	$ 1,280	$ 0
Depositary Shares, Liquidation Preference Per Share	$ 100.00
Payments of preferred stock				$ 20,127	$ 0
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, authorized (in shares)		1,000,000		1,000,000		1,000,000
Preferred stock, issued (in shares)		763,500		763,500		770,000
Depositary share repurchased during period, share		65,000
Depositary share repurchased during period, value		$ 5,000
Depositary share repurchased during period at an average price per share		$ 77.31
Gain on repurchase of mandatory convertible preferred stock		$ 1,280
Depository shares equivalent to preferred stock units (in shares)		6,500		6,500
Depositary shares (in shares)	7,700,000
Preferred stock, dividend rate	5.25%
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01		$ 0.01		$ 0.01
Issuance of preferred stock (in dollars per share)	$ 100.00
Gross proceeds from issuance of preferred stock	$ 770,000
Preferred stock, liquidation preference (in dollars per share)	$ 1,000
Payments of preferred stock		$ 10,000		$ 20,100
Series A Preferred Stock | Minimum
Class of Stock [Line Items]
Common stock issuable upon conversion (in shares)	5.8716
Series A Preferred Stock | Maximum
Class of Stock [Line Items]
Common stock issuable upon conversion (in shares)	7.3394