Equity - Common Stock Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Aug. 03, 2017	Sep. 08, 2015
Class of Stock [Line Items]
Dividends, Common Stock, Cash	$ 0.36	$ 0.26	$ 11,435,000	$ 8,145,000
Dividends, Preferred Stock, Cash			$ 9,886,000	$ 9,886,000
Common Class C, Non-Voting [Member]
Class of Stock [Line Items]
Stock Repurchase Program, Authorized Amount					$ 5,400,000	$ 25,000,000
Repurchase of Class C Common Stock			668,000
Stock Repurchased and Retired During Period, Value	19,600,000		$ 19,600,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Dividends, Preferred Stock, Cash	0.3672	0.3672
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Dividends, Preferred Stock, Cash	0.4297	0.4297
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Dividends, Preferred Stock, Cash	$ 0.3750	$ 0.3750