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SUBSEQUENT EVENTS (Details) - USD ($)						3 Months Ended	12 Months Ended
SUBSEQUENT EVENTS (Details) - USD ($)	Mar. 08, 2017	Feb. 17, 2017	Feb. 14, 2017	Feb. 13, 2017	Dec. 23, 2013	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Dividends declared
Cash dividend declared (in dollars per share)							$ 0.80	$ 0.80	$ 0.60
Other General and Administrative Expenses
Litigation Settlement
Litigation settlement amount						$ 7,000,000
Subsequent Events
Additional Public Offering
Repayment of Bridge Loan				$ 350,000,000
Subsequent Events \| Other General and Administrative Expenses
Litigation Settlement
Litigation settlement amount	$ 7,000,000
Class A Common Stock
Additional Public Offering
Number of shares issued					21,052,632
Class A Common Stock \| Subsequent Events
Additional Public Offering
Number of shares issued		1,283,255		19,047,619
Price per share		$ 31.50		$ 31.50
Value of shares issued		$ 40,423,000		$ 600,000,000
Net proceeds		$ 39,000,000		579,000,000
Repayment of Bridge Loan				$ 350,000,000
Dividends declared
Cash dividend declared (in dollars per share)			$ 0.20
Class A Common Stock \| Subsequent Events \| Mr. Aron
Additional Public Offering
Number of shares issued				31,747
Price per share				$ 31.50
Class B Common Stock \| Subsequent Events
Dividends declared
Cash dividend declared (in dollars per share)			$ 0.20