UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (DEFECIT) - USD ($) $ in Thousands | Total | Common Class A | Common Class B | Common StockCommon Class A | Common StockCommon Class B | Treasury Stock | Paid-in-Capital | Retained Earnings (Deficit) | Accumulated Other Comprehensive Income (Loss) |
Common stock, shares, beginning of period (in shares) at Dec. 31, 2017 | | | | 34,173,000 | 291,000 | | | | |
Stockholders' equity beginning of period at Dec. 31, 2017 | $ 746,000 | | | $ 0 | $ 0 | $ 0 | $ 676,000 | $ (62,000) | $ 132,000 |
Treasury shares, beginning of period (in shares) at Dec. 31, 2017 | | | | | | 9,000 | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | | | |
Net income (loss) | 85,000 | | | | | | | 85,000 | |
Other comprehensive income (loss), net | 1,000 | | | | | | | | 1,000 |
Treasury shares (in shares) | | | | | | 7,000 | | | |
Treasury shares | $ 0 | | | | | | | | |
Common stock issued for restricted stock (in shares) | 0 | | | 106,000 | | | | | |
Class B stock converted to Class A stock (in shares) | 0 | | | 291,000 | (291,000) | | | | |
Equity award expense | $ 6,000 | | | | | | 6,000 | | |
Common stock, shares, end of period (in shares) at Sep. 30, 2018 | | | | 34,570,000 | 0 | | | | |
Stockholders' equity end of period at Sep. 30, 2018 | 838,000 | | | $ 0 | $ 0 | $ 0 | 682,000 | 16,000 | 140,000 |
Treasury shares, end the period (in shares) at Sep. 30, 2018 | | | | | | 16,000 | | | |
Common stock, shares, beginning of period (in shares) at Jun. 30, 2018 | | | | 34,544,000 | 0 | | | | |
Stockholders' equity beginning of period at Jun. 30, 2018 | 750,000 | | | $ 0 | $ 0 | $ 0 | 680,000 | (70,000) | 140,000 |
Treasury shares, beginning of period (in shares) at Jun. 30, 2018 | | | | | | 9,000 | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | | | |
Net income (loss) | 86,000 | | | | | | | 86,000 | |
Treasury shares | $ 0 | | | | | | | | |
Common stock issued for restricted stock (in shares) | 0 | | | 26,000 | | | | | |
Equity award expense | $ 2,000 | | | | | | 2,000 | | |
Common stock, shares, end of period (in shares) at Sep. 30, 2018 | | | | 34,570,000 | 0 | | | | |
Stockholders' equity end of period at Sep. 30, 2018 | 838,000 | | | $ 0 | $ 0 | $ 0 | 682,000 | 16,000 | 140,000 |
Treasury shares, end the period (in shares) at Sep. 30, 2018 | | | | | | 16,000 | | | |
Common stock, shares, beginning of period (in shares) at Dec. 31, 2018 | | 34,569,917 | 0 | 34,570,000 | 0 | | | | |
Stockholders' equity beginning of period at Dec. 31, 2018 | $ 906,000 | | | $ 0 | $ 0 | $ (2,000) | 686,000 | 102,000 | 120,000 |
Treasury shares, beginning of period (in shares) at Dec. 31, 2018 | 85,824 | | | | | 86,000 | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | | | |
Net income (loss) | $ (46,000) | | | | | | | (46,000) | |
Treasury shares (in shares) | | | | | | 159,000 | | | |
Treasury shares | $ (3,000) | | | | | $ (3,000) | | | |
Common stock issued for restricted stock (in shares) | 0 | | | 366,000 | | | | | |
Equity award expense | $ 10,000 | | | | | | 10,000 | | |
Common stock, shares, end of period (in shares) at Sep. 30, 2019 | | 34,936,378 | 0 | 34,936,000 | 0 | | | | |
Stockholders' equity end of period at Sep. 30, 2019 | $ 867,000 | | | $ 0 | $ 0 | $ (5,000) | 696,000 | 56,000 | 120,000 |
Treasury shares, end the period (in shares) at Sep. 30, 2019 | 245,063 | | | | | 245,000 | | | |
Common stock, shares, beginning of period (in shares) at Jun. 30, 2019 | | | | 34,911,000 | 0 | | | | |
Stockholders' equity beginning of period at Jun. 30, 2019 | $ 835,000 | | | $ 0 | $ 0 | $ (5,000) | 694,000 | 26,000 | 120,000 |
Treasury shares, beginning of period (in shares) at Jun. 30, 2019 | | | | | | 238,000 | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | | | |
Net income (loss) | 30,000 | | | | | | | 30,000 | |
Treasury shares (in shares) | | | | | | 7,000 | | | |
Treasury shares | $ 0 | | | | | | | | |
Common stock issued for restricted stock (in shares) | 0 | | | 25,000 | | | | | |
Equity award expense | $ 2,000 | | | | | | 2,000 | | |
Common stock, shares, end of period (in shares) at Sep. 30, 2019 | | 34,936,378 | 0 | 34,936,000 | 0 | | | | |
Stockholders' equity end of period at Sep. 30, 2019 | $ 867,000 | | | $ 0 | $ 0 | $ (5,000) | $ 696,000 | $ 56,000 | $ 120,000 |
Treasury shares, end the period (in shares) at Sep. 30, 2019 | 245,063 | | | | | 245,000 | | | |