Condensed Consolidated Statements of Equity - USD ($) $ in Thousands | Total | Common Stock | Additional Paid-in Capital | Accumulated Deficit | Accumulated Other Comprehensive Income | Treasury Stock | Noncontrolling Interest |
Beginning balance (in shares) at Dec. 31, 2016 | | 23,125,000 | | | | | |
Beginning balance at Dec. 31, 2016 | $ 427,569 | $ 23 | $ 495,468 | $ (173,231) | $ 6,661 | $ (927) | $ 99,575 |
Beginning balance, treasury stock (in shares) at Dec. 31, 2016 | | | | | | 55,000 | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Stock-based compensation expense | 1,565 | | 1,334 | | | | 231 |
Exercise of restricted stock units (in shares) | | 62,000 | | | | | |
Exercise of restricted stock units | 0 | | | | | | |
Withholding taxes paid on vested restricted stock units | (832) | | (711) | | | | (121) |
Changes in ownership of noncontrolling interest | 0 | | (465) | | | | 465 |
Acquisition of interests held by noncontrolling owners | 0 | | | | | | |
Distribution of treasury stock to deferred compensation plan participants (in shares) | | | | | | (54,000) | |
Distribution of treasury stock to deferred compensation plan participants | 796 | | (106) | | | $ 902 | |
Distribution to noncontrolling interest | (26) | | | | | | (26) |
Purchases of treasury stock (in shares) | | | | | | 47,000 | |
Purchases of treasury stock | (690) | | | | | $ (690) | |
Retirement of treasury stock (in shares) | | (47,000) | | | | (47,000) | |
Retirement of treasury stock | 0 | | (690) | | | $ 690 | |
Net income (loss) | 9,015 | | | 6,219 | | | 2,796 |
Unrealized loss on investments, net of deferred income tax of $3,176 and reclassification adjustments of $9,179 | (5,899) | | | | (5,899) | | |
Foreign currency translation | 25 | | | | 25 | | |
Ending balance (in shares) at Jun. 30, 2017 | | 23,140,000 | | | | | |
Ending balance at Jun. 30, 2017 | 431,523 | $ 23 | 494,830 | (167,012) | 787 | $ (25) | 102,920 |
Ending balance, treasury stock (in shares) at Jun. 30, 2017 | | | | | | 1,000 | |
Beginning balance at Mar. 31, 2017 | | | | | 6,087 | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Net income (loss) | 2,980 | | | | | | |
Ending balance (in shares) at Jun. 30, 2017 | | 23,140,000 | | | | | |
Ending balance at Jun. 30, 2017 | 431,523 | $ 23 | 494,830 | (167,012) | 787 | $ (25) | $ 102,920 |
Ending balance, treasury stock (in shares) at Jun. 30, 2017 | | | | | | 1,000 | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Reclassification of unrealized gain on investments to accumulated deficit | $ 16 | | | 560 | (544) | | |
Beginning balance (in shares) at Dec. 31, 2017 | 23,153,000 | 23,154,000 | | | | | |
Beginning balance at Dec. 31, 2017 | $ 207,163 | $ 23 | 379,388 | (172,767) | 544 | $ (25) | |
Beginning balance, treasury stock (in shares) at Dec. 31, 2017 | 1,000 | | | | | 1,000 | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Stock-based compensation expense | $ 300 | | 300 | | | | |
Exercise of restricted stock units (in shares) | | 23,000 | | | | | |
Exercise of restricted stock units | 0 | | | | | | |
Purchases of treasury stock (in shares) | | | | | | 1,155,000 | |
Purchases of treasury stock | (12,945) | | | | | $ (12,945) | |
Retirement of treasury stock (in shares) | | (1,155,000) | | | | (1,155,000) | |
Retirement of treasury stock | 0 | $ (1) | (12,944) | | | $ 12,945 | |
Net income (loss) | $ 1,440 | | | 1,440 | | | |
Ending balance (in shares) at Jun. 30, 2018 | 22,022,000 | 22,022,000 | | | | | |
Ending balance at Jun. 30, 2018 | $ 195,974 | $ 22 | 366,744 | (170,767) | 0 | $ (25) | |
Ending balance, treasury stock (in shares) at Jun. 30, 2018 | 1,000 | | | | | 1,000 | |
Beginning balance at Mar. 31, 2018 | | | | | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Net income (loss) | $ 4,302 | | | | | | |
Ending balance (in shares) at Jun. 30, 2018 | 22,022,000 | 22,022,000 | | | | | |
Ending balance at Jun. 30, 2018 | $ 195,974 | $ 22 | $ 366,744 | $ (170,767) | $ 0 | $ (25) | |
Ending balance, treasury stock (in shares) at Jun. 30, 2018 | 1,000 | | | | | 1,000 | |