Shareholders' Equity - Distributions (Details) - $ / shares	1 Months Ended					2 Months Ended	12 Months Ended
	Jul. 31, 2016	Jun. 30, 2016	May 31, 2016	May 31, 2014	Oct. 31, 2013	Jan. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class B common shares
Class of Stock [Line Items]
Dividend payable per share (in dollars per share)							$ 0.20	$ 0.20	$ 0.20
Class A common shares
Class of Stock [Line Items]
Dividend payable per share (in dollars per share)							0.20	0.2	0.2
Series A Participating Preferred Stock
Class of Stock [Line Items]
Dividend payable per share (in dollars per share)							$ 1.25	$ 1.25	$ 1.25
Preferred Shares dividend rate					5.00%		5.00%	5.00%	5.00%
Series B Participating Preferred Stock
Class of Stock [Line Items]
Dividend payable per share (in dollars per share)							$ 1.25	$ 1.25	$ 1.2875
Preferred Shares dividend rate						5.00%	5.00%	5.00%	5.00%
Series C Participating Preferred Stock
Class of Stock [Line Items]
Dividend payable per share (in dollars per share)							$ 1.375	$ 1.375	$ 0.912847
Preferred Shares dividend rate				5.50%			5.50%	5.50%	5.50%
Series D Perpetual Preferred Stock
Class of Stock [Line Items]
Preferred Shares dividend rate			6.50%				6.50%
Preferred stock, dividends per share, declared (in dollars per share)							$ 0.98403
Series E Perpetual Preferred Stock
Class of Stock [Line Items]
Preferred Shares dividend rate	6.35%	6.35%					6.35%
Preferred stock, dividends per share, declared (in dollars per share)							$ 0.80257
Series D Convertible Units
Class of Stock [Line Items]
Dividend payable per share (in dollars per share)							0.11
Series C Convertible Units
Class of Stock [Line Items]
Dividend payable per share (in dollars per share)							$ 0.06517	$ 0.60452	$ 0.60452