Quarterly Financial Data - Summary of Condensed Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Jun. 30, 2015 |
Mar. 31, 2015 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
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| Quarterly Financial Information Disclosure [Abstract] | |||||||||||
| Operating revenues, net | $ 144,853 | $ 158,093 | $ 167,136 | $ 164,016 | $ 186,751 | $ 214,733 | $ 198,547 | $ 204,197 | $ 634,098 | $ 804,228 | $ 836,270 |
| (Loss) gain on disposition of assets, net | (504) | (85) | 4,298 | (359) | (577) | 165 | 66 | 7 | 3,350 | (339) | (848) |
| (Loss) earnings before income taxes | (12,012) | (7,766) | 117 | (7,488) | 938 | 14,290 | 11,044 | 16,984 | (27,149) | 43,256 | 53,115 |
| Net (loss) earnings | (17,058) | (4,967) | 4,277 | (8,932) | 2,438 | 7,669 | 6,454 | 10,363 | (26,680) | 26,924 | 32,688 |
| Net (loss) earnings per share | |||||||||||
| Operating revenues, net | 144,853 | 158,093 | 167,136 | 164,016 | 186,751 | 214,733 | 198,547 | 204,197 | 634,098 | 804,228 | 836,270 |
| Gain (loss) on disposition of assets, net | (504) | (85) | 4,298 | (359) | (577) | 165 | 66 | 7 | 3,350 | (339) | (848) |
| Earnings before income taxes | (12,012) | (7,766) | 117 | (7,488) | 938 | 14,290 | 11,044 | 16,984 | (27,149) | 43,256 | 53,115 |
| Net earnings | $ (17,058) | $ (4,967) | $ 4,277 | $ (8,932) | $ 2,438 | $ 7,669 | $ 6,454 | $ 10,363 | $ (26,680) | $ 26,924 | $ 32,688 |
| Basic | $ (1.08) | $ (0.32) | $ 0.27 | $ (0.57) | $ 0.16 | $ 0.49 | $ 0.41 | $ 0.67 | |||
| Diluted | $ (1.08) | $ (0.32) | $ 0.27 | $ (0.57) | $ 0.16 | $ 0.49 | $ 0.41 | $ 0.66 | |||
| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The amount of net income (loss) from extraordinary items, net of related tax effect, per each share of common stock or unit outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The amount of net income (loss) for the period attributable to extraordinary items that is available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- References No definition available.
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| X | ||||||||||
- Definition Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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