Restructuring Expenses (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2016 |
Dec. 31, 2016 |
|
| Restructuring Cost and Reserve [Line Items] | |||||
| Restructuring expenses | $ 538 | $ 1,324 | $ 1,437 | $ 3,572 | $ 6,020 |
| Fleet and Property, Plant and Equipment Abandonment Costs | |||||
| Restructuring Cost and Reserve [Line Items] | |||||
| Restructuring expenses | 2 | 108 | 109 | ||
| Severance and Benefits | |||||
| Restructuring Cost and Reserve [Line Items] | |||||
| Restructuring expenses | 164 | 236 | 1,006 | ||
| Lease Abandonment Costs | |||||
| Restructuring Cost and Reserve [Line Items] | |||||
| Restructuring expenses | 189 | 1,077 | 705 | 1,813 | 3,453 |
| Other Costs | |||||
| Restructuring Cost and Reserve [Line Items] | |||||
| Restructuring expenses | $ 349 | $ 81 | $ 732 | $ 1,415 | $ 1,452 |