EQUITY (Details) (USD $)	6 Months Ended		12 Months Ended	6 Months Ended	12 Months Ended	0 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended		0 Months Ended				6 Months Ended		0 Months Ended
	Jun. 30, 2013	Jun. 30, 2014 Series A Cumulative Redeemable Preferred Stock	Dec. 31, 2013 Series A Cumulative Redeemable Preferred Stock	Jun. 30, 2014 Series B Cumulative Redeemable Preferred Stock	Dec. 31, 2013 Series B Cumulative Redeemable Preferred Stock	Mar. 20, 2013 Series C Cumulative Redeemable Preferred Stock	Jun. 30, 2014 Series C Cumulative Redeemable Preferred Stock	Dec. 31, 2013 Series C Cumulative Redeemable Preferred Stock	Jun. 30, 2014 Common Stock	Jun. 30, 2013 Common Stock	May 28, 2014 Common Stock Executive officers and management	Mar. 01, 2013 Common Stock Executive officers	Jun. 17, 2014 Common Stock Director	Jun. 13, 2013 Common Stock Director	Jun. 30, 2014 Common Stock Director	Jun. 30, 2013 Common Stock Director	Jan. 14, 2013 Common Stock Public offering
Equity
Shares of common stock issued to redeem common units									151,504	2,228,544
New issued stock (in shares)						3,400,000											17,250,000
Stock issued to officers and directors (in shares)									303,329	324,341	278,916	292,090	20,349	29,228
Shares issued in lieu of cash for director fees															4,064	3,023
Proceeds from equity offerings, net of offering costs	$ 237,262,000					$ 81,700,000											$ 148,100,000
Underwriting discount and offering-related expenses						$ 3,300,000											$ 7,200,000
Preferred stock, dividend rate (as a percent)		9.25%	9.25%	7.875%	7.875%	7.125%	7.125%	7.125%
Preferred stock, liquidation preference (in dollars per share)		$ 25		$ 25			$ 25
Annual dividend rate per share (in dollars per share)		$ 2.3125		$ 1.96875			$ 1.78125