Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Plans - Outstanding Awards Under 2013 Omnibus Equity Incentive Plan (Detail)

v3.19.1
Stock-Based Compensation Plans - Outstanding Awards Under 2013 Omnibus Equity Incentive Plan (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended
Feb. 28, 2018
Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Nonvested shares at December 31, 2018   891,575
Granted 211,791 211,791
Vested   (290,396)
Transferred   0
Forfeited/canceled   (15,044)
Nonvested shares at March 31, 2019   797,926
Unrecognized stock-based compensation expense as of March 31, 2019   $ 24,552
Weighted average remaining vesting period (years) as of March 31, 2019   3 years 8 months 4 days
Nonvested weighted average grant date fair value per share, beginning balance   $ 27.59
Weighted average grant date fair value per share, Granted   39.45
Weighted average grant date fair value, Vested   21.74
Weighted average grant date fair value, Transferred   28.80
Weighted average grant date fair value, Forfeited/canceled   32.17
Nonvested weighted average grant date fair value per share, ending balance   $ 32.78
Restricted Stock Awards [Member] | Non-Employee Directors [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Nonvested shares at December 31, 2018   27,096
Granted 0 0
Vested   0
Transferred   0
Forfeited/canceled   0
Nonvested shares at March 31, 2019   27,096
Unrecognized stock-based compensation expense as of March 31, 2019   $ 182
Weighted average remaining vesting period (years) as of March 31, 2019   9 months 21 days
Restricted Stock Units [Member] | Employees [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Nonvested shares at December 31, 2018   471,782
Granted 204,060 204,060
Vested   (152,816)
Transferred   (4,915)
Forfeited/canceled   (3,277)
Nonvested shares at March 31, 2019   514,834
Unrecognized stock-based compensation expense as of March 31, 2019   $ 16,149
Weighted average remaining vesting period (years) as of March 31, 2019   3 years 11 months 1 day
Restricted Stock Units [Member] | Independent Contractors, Prior to Adoption of New Standard [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Nonvested shares at December 31, 2018   392,697
Granted 7,731 7,731
Vested   (137,580)
Transferred   4,915
Forfeited/canceled   (11,767)
Nonvested shares at March 31, 2019   255,996
Unrecognized stock-based compensation expense as of March 31, 2019   $ 8,221
Weighted average remaining vesting period (years) as of March 31, 2019   3 years 3 months 7 days