Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans - Amendments to Restricted Stock and SARs - Additional Information (Detail)

v3.6.0.2
Stock-Based Compensation Plans - Amendments to Restricted Stock and SARs - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2016
shares
Deferred stock units [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Employee termination age 67 years
DSU settlement to common stock percentage 20.00%
DSU settlement into actual stock issued term 5 years
Percentage of shares of deferred stock units settled in the event of death or termination after reaching age 67 100.00%
Restricted Stock Sales Restriction [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Sales restriction lapse percentage for restricted stock 20.00%
Employee termination age 67 years
Sales restriction period for restricted stock 5 years
Percentage of shares of stock released from resale restriction upon consummation of change of control 100.00%
Percentage of shares of restricted released from resale restriction in the event of death or termination after reaching age 67 100.00%
Number of original shares subject to resale restriction 3,689,326
Number of shares remain subject to sales restriction 1,475,730