CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common stock (in dollars per share)	$ 1.78	$ 1.71	$ 1.65
Stock issued during period, shares	31,807	34,230	5,493,595
ATM equity program, shares	5,716,222	8,573,533	3,758,362
Discounted stock purchase program, shares	8,444	12,065	100,161
Restricted common stock, shares	222,157	209,284	360,808
Series D Depositary Share
Series D preferred stock (in USD per share)	$ 1.65625	$ 1.65625	$ 1.65625
Depositary shares issued (in shares)	115,000	115,000
Series E Depositary Share
Series D preferred stock (in USD per share)	$ 1.42500	$ 1.42500	$ 1.42500
Depositary shares issued (in shares)	115,000	115,000
Series F Preferred Stock
Series D preferred stock (in USD per share)	$ 0.231111	$ 0.231111
Depositary shares issued (in shares)	138,000	0