Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Plans - Stock-Based Compensation Expense (Detail)

v3.5.0.2
Stock-Based Compensation Plans - Stock-Based Compensation Expense (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2016
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation expense - Independent contractors $ 788 $ 1,979 $ 1,318 $ 3,238
Allocated share-based compensation expense 1,775 2,675 3,100 4,582
Employee Stock Purchase Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense 60 66 108 128
Restricted Stock Awards [Member] | Non-Employee Directors [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense 109 78 198 137
Restricted Stock Units (RSUs) [Member] | Employees [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Allocated share-based compensation expense $ 818 $ 552 $ 1,476 $ 1,079