XML 105 R88.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stockholders' Equity - Additional Information (Detail) - shares
 12 Months Ended
Dec. 14, 2015
Dec. 31, 2017
Dec. 31, 2016
Class of Stock [Line Items]      
Preferred stock authorized   5,000,000 5,000,000
Preferred stock, shares issued   0 0
Preferred stock, shares outstanding   0 0
Common stock repurchased and retired, shares   0 0
Privately Negotiated Transactions [Member]      
Class of Stock [Line Items]      
Common stock repurchased and retired, shares 11,100,000