Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Plans - 2013 Omnibus Equity Incentive Plan - Additional Information (Detail)

v3.8.0.1
Stock-Based Compensation Plans - 2013 Omnibus Equity Incentive Plan - Additional Information (Detail)
3 Months Ended
Mar. 31, 2018
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vested shares 258,930
2013 Omnibus Equity Incentive Plan [Member] | Options [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of shares issued under compensation plan 0
Number of shares outstanding under compensation plan 0
2013 Omnibus Equity Incentive Plan [Member] | Deferred stock units [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Fully vested deferred stock units remaining outstanding 578,618
2013 Omnibus Equity Incentive Plan [Member] | Restricted Stock Awards [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period 1 year
2013 Omnibus Equity Incentive Plan [Member] | Restricted Stock Awards [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period 3 years
2013 Omnibus Equity Incentive Plan [Member] | Restricted Stock Units [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vesting period 5 years
Vested shares 258,930
Number of common stock shares withheld to pay employee statutory withholding taxes 48,107
Vested and delivered shares 252,930
2013 Omnibus Equity Incentive Plan [Member] | SARs [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of shares issued under compensation plan 0
Number of shares outstanding under compensation plan 0
2013 Omnibus Equity Incentive Plan [Member] | Performance Shares [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of shares issued under compensation plan 0
Number of shares outstanding under compensation plan 0
2013 Omnibus Equity Incentive Plan [Member] | Performance Units [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Number of shares issued under compensation plan 0
Number of shares outstanding under compensation plan 0