Shareholders' Equity - Participating Preferred Shares (Details) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($) market
Class of Stock [Line Items]
Cumulative change in value of index based on purchase prices	50.00%
Number of top markets used for purchase price index | market	20
Liquidation preference value | $	$ 460.2
5.0% Series A Participating Preferred Shares
Class of Stock [Line Items]
Preferred stock, dividend rate, percentage	5.00%
5.0% Series B Participating Preferred Shares
Class of Stock [Line Items]
Preferred stock, dividend rate, percentage	5.00%
5.5% Series C Participating Preferred Shares
Class of Stock [Line Items]
Preferred stock, dividend rate, percentage	5.50%