Quarterly report pursuant to Section 13 or 15(d)

Mandatorily Redeemable Term Preferred Stock - Additional Information (Detail)

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Mandatorily Redeemable Term Preferred Stock - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Millions
 1 Months Ended 12 Months Ended
Feb. 29, 2012
Dec. 31, 2016
Class of Stock [Line Items]    
Write-off of deferred offering costs   $ 0.2
Series C Preferred Stock    
Class of Stock [Line Items]    
Redeemable preferred stock, dividend rate percentage (as percent) 7.125%  
Mandatorily redeemable preferred stock    
Class of Stock [Line Items]    
Redeemable preferred stock, shares issued (in shares) 1,540,000  
Redeemable preferred stock, par value (in dollars per share) $ 0.001  
Public offering price (in dollars per share) $ 25.00  
Gross proceeds of the offering $ 38.5  
Net proceeds, after deducting offering expenses $ 36.7