XML 58 R48.htm IDEA: XBRL DOCUMENT v3.10.0.1
Summary of Stock Option Activity (Parenthetical) (Detail) - shares
 9 Months Ended
Sep. 30, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Outstanding amount of stock appreciation right units [2] 707,415 [1] 729,017
Exercisable amount of stock appreciation right units [2],[3] 610,731  
Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Outstanding amount of stock appreciation right units 645,874  
Exercisable amount of stock appreciation right units 553,861  
Stock Appreciation Rights (SARs) | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Maximum percentage of stock appreciation right units 75.00%  
[1] Due to the ceiling imposed on the SAR grants, the outstanding amount equals a maximum of 645,874 shares of the Company's common stock issuable upon exercise.
[2] The SAR units are convertible for a maximum number of shares of the Company's common stock equal to 75% of the SAR units subject to the grant.
[3] Due to the ceiling imposed on the SAR grants, the exercisable amount equals a maximum of 553,861 shares of the Company's common stock issuable upon exercise.