Quarterly report pursuant to Section 13 or 15(d)

Equity (Exchangeable Shares and Series F and Series G Preferred Stock) - Additional Information (Detail)

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Equity (Exchangeable Shares and Series F and Series G Preferred Stock) - Additional Information (Detail) - shares
 3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Class of Stock [Line Items]      
Minimum number of shares that can be exchanged by exchangeable shareholders unless the number of remaining exchangeable shares registered in the name of the holder is less 50,000    
Number of shares of Common stock received for each exchangeable share 1    
Common stock, shares outstanding 148,109,496   144,710,773
Series F Preferred Stock [Member]      
Class of Stock [Line Items]      
Preferred stock, shares outstanding 1   1
Series G Preferred Stock [Member]      
Class of Stock [Line Items]      
Preferred stock, shares outstanding 1   1
Exchangeable Shares [Member]      
Class of Stock [Line Items]      
Common stock, shares outstanding 3,986,112   6,515,453
Series F and Series G Preferred Stock [Member]      
Class of Stock [Line Items]      
Exchangeable stock shares outstanding 3,900,000    
Exchangeable Shares [Member]      
Class of Stock [Line Items]      
Exchangeable shares exchanged for common stock 2,500,000 0.0