Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Quarterly Financial Information Disclosure [Abstract] | |||||||||||||||||||||
| Revenues | $ 143,422 | $ 153,459 | $ 149,612 | $ 134,213 | $ 129,099 | $ 110,281 | $ 123,323 | $ 124,393 | |||||||||||||
| Operating income (loss) | 102,674 | 57,147 | 48,467 | 38,739 | 33,166 | 15,700 | 32,888 | 28,196 | $ 247,027 | $ 109,950 | $ (330,568) | ||||||||||
| Net income (loss) | $ 138,844 | [1] | $ 46,260 | [1] | $ 36,083 | [1] | $ 27,640 | [1] | $ 23,365 | [1] | $ (1,297) | [1] | $ 33,315 | [1] | $ 24,299 | [1] | $ 248,827 | $ 79,682 | $ (249,020) | ||
| Basic and diluted earnings per common share | $ 0.96 | $ 0.32 | $ 0.25 | $ 0.19 | $ 0.16 | $ (0.01) | $ 0.23 | $ 0.17 | $ 1.72 | $ 0.56 | $ (2.60) | ||||||||||
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- Definition The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period 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/2009/role/commonPracticeRef
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- 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/disclosureRef
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- Definition The net result for the period of deducting operating expenses from operating revenues. No definition available.
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- References No definition available.
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- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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