EQUITY (Details) (USD $)	0 Months Ended				3 Months Ended	6 Months Ended
	May 12, 2014	May 05, 2014	Jan. 23, 2014	Mar. 21, 2013	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Equity [Line Items]
Stock issuance, Shares	8,100,000
Stock issuance, Shares, Underwriters option	1,100,000
Preferred stock, shares issued				5,800,000	5,750,000	5,750,000		5,750,000
Common dividends, declared		$ 0.38	$ 0.36			$ 0.74	$ 0.68
Shares Paid for Tax Withholding for Share Based Compensation						5,100,000
Preferred Stock, Dividend Rate, Percentage						7.125%
Preferred Stock, Redemption Price Per Share				$ 25.00
Issuance of preferred stock				$ 138,300,000		$ 0	$ 138,345,000
Convertible Preferred Stock, Terms of Conversion						1.7864
Common Stock, At The Market Stock Offering, Max Possible Gross Proceeds						100,000,000
Common Stock, At the Market Stock Offering, Sales Commision						2.00%
Common Stock, At the Market Stock Offering, Number of Shares Sold					100,000	200,000
Sale of Stock, Price Per Share	$ 28.35
Proceeds from Issuance of Common Stock	219,100,000					219,899,000	(2,851,000)
Restricted Stock Units (RSUs) [Member]
Equity [Line Items]
Stock-based compensation, issued during period (in shares)						200,000.0
Stock Options [Member]
Equity [Line Items]
Stock-based compensation, issued during period (in shares)						11,515
At-the-Market Offering, Sales Agents [Member]
Equity [Line Items]
Share Price					$ 27.77	$ 27.71
Proceeds from Issuance of Common Stock					1,900,000	6,600,000
Payments of Stock Issuance Costs					39,000	100,000
Common Stock, Amount Available for Future Issuance						$ 55,200,000