Accrued Restructuring Obligations and Related Activity (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] |
|
|
|
|
|
| Accrued obligations, beginning balance |
|
|
$ 763
|
$ 1,742
|
$ 1,742
|
| Restructuring expense |
$ 538
|
$ 1,324
|
1,437
|
3,572
|
6,020
|
| Settlement of obligations |
|
|
(1,823)
|
|
(6,999)
|
| Accrued obligations, ending balance |
377
|
|
377
|
|
763
|
| Fleet and Property, Plant and Equipment Abandonment Costs |
|
|
|
|
|
| Restructuring Cost and Reserve [Line Items] |
|
|
|
|
|
| Restructuring expense |
|
2
|
|
108
|
109
|
| Settlement of obligations |
|
|
|
|
(109)
|
| Severance and Benefits |
|
|
|
|
|
| Restructuring Cost and Reserve [Line Items] |
|
|
|
|
|
| Accrued obligations, beginning balance |
|
|
395
|
1,245
|
1,245
|
| Restructuring expense |
|
164
|
|
236
|
1,006
|
| Settlement of obligations |
|
|
(332)
|
|
(1,856)
|
| Accrued obligations, ending balance |
63
|
|
63
|
|
395
|
| Lease Abandonment Costs |
|
|
|
|
|
| Restructuring Cost and Reserve [Line Items] |
|
|
|
|
|
| Accrued obligations, beginning balance |
|
|
368
|
495
|
495
|
| Restructuring expense |
189
|
1,077
|
705
|
1,813
|
3,453
|
| Settlement of obligations |
|
|
(807)
|
|
(3,580)
|
| Accrued obligations, ending balance |
266
|
|
266
|
|
368
|
| Other Costs |
|
|
|
|
|
| Restructuring Cost and Reserve [Line Items] |
|
|
|
|
|
| Accrued obligations, beginning balance |
|
|
|
2
|
2
|
| Restructuring expense |
349
|
$ 81
|
732
|
$ 1,415
|
1,452
|
| Settlement of obligations |
|
|
(684)
|
|
$ (1,454)
|
| Accrued obligations, ending balance |
$ 48
|
|
$ 48
|
|
|