Subsequent Events (Details) - $ / shares			12 Months Ended
	Feb. 21, 2017	Nov. 01, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Dividends declared per common share (in dollars per share)		$ 0.15	$ 0.57	$ 0.53	$ 0.46
Subsequent event
Subsequent Event [Line Items]
Dividends declared per common share (in dollars per share)	$ 0.15
Subsequent event | Preference shares – Series A
Subsequent Event [Line Items]
Dividends declared per Preference share (in dollars per share)	0.515625
Subsequent event | Preference shares – Series C
Subsequent Event [Line Items]
Dividends declared per Preference share (in dollars per share)	$ 0.445313