Equity - Narrative (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended			3 Months Ended		3 Months Ended
	Mar. 31, 2014 class_of_stock	Mar. 31, 2013	Mar. 31, 2014 Common Class A, Voting [Member]	Mar. 31, 2014 Series A Preferred Stock [Member]	Dec. 31, 2013 Series A Preferred Stock [Member]	Mar. 31, 2014 Series B Preferred Stock [Member]	Dec. 31, 2013 Series B Preferred Stock [Member]
Class of Stock [Line Items]
Number of Classes of Common Stock	3
Common Stock, Maximum Ownership Percentage by a Beneficial Owner			33.00%
Common stock dividend, per share, cash paid	$ 0.14	$ 0.12
Preferred Stock, shares issued				2,400,000	2,400,000	3,000,000	0
Preferred Stock, Dividend Rate, Percentage				5.875%		6.875%
Payments of Stock Issuance Costs				$ 1.7		$ 1.7
Preferred Stock, Par or Stated Value Per Share				$ 25	$ 25	$ 25	$ 0
Preferred Stock, Liquidation Preference Per Share				$ 25		$ 25
Preferred Stock, shares outstanding				2,400,000	2,400,000	3,000,000	0