Stock-Based Compensation Stock-based Compensation Expense (Detail) - USD ($)
$ in Thousands
Mar. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
2016 $ 1,458 $ 1,857
2017 1,865 1,709
2018 331 309
2019 135 121
2020 60 51
Total $ 3,849 $ 4,047