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Share Repurchase Program - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Class of Stock Disclosures [Abstract]    
Purchase of treasury stock, shares 41,322 0
Purchase of treasury stock, per share value $ 35.31  
Purchase of treasury stock $ 1,459  
Common stock shares, available for repurchase 269,734