CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Common stock dividend, per share, cash paid	$ 0.56	$ 0.48	$ 0.40
Series A Preferred Stock [Member]
Preferred stock (in usd per share)	$ 1.4688	$ 1.3994	$ 0
Series B Preferred Stock [Member]
Preferred stock (in usd per share)	$ 1.3129	$ 0	$ 0
Series C Preferred Stock [Member]
Preferred stock (in usd per share)	$ 0.7917	$ 0	$ 0
Retired Series C Preferred Stock [Member]
Preferred stock (in usd per share)	$ 0	$ 2.36	$ 50