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Stockholder's Equity - Additional Information (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 1 Months Ended 12 Months Ended
Mar. 13, 2015
Mar. 31, 2015
Dec. 31, 2017
Dec. 31, 2015
Statement Of Shareholders Equity [Line Items]        
Effective portion of unrealized gain on derivative instruments     $ 507  
Share repurchase, amount       $ 6,100
IBS [Member]        
Statement Of Shareholders Equity [Line Items]        
Common Stock Repurchase, Shares 315 315    
Share repurchase, amount   $ 6,100    
Share repurchase, price per share $ 19.23      
Discount from last reported price of our common stock 7.50%