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Income Taxes and Deferred Tax Asset/Liability - Summary Reconciliation Reported Amount of Income Tax Expense (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Amount [Abstract] |  |  |
Tax expense (benefit) at the U.S. federal statutory rate | $ 5,577 | $ (2,563) | $ (6,013)
State tax based on income, net of refunds and federal benefits | (264) | (113) | (860)
Taxes on subsidiaries’ and joint ventures’ earnings allocated to noncontrolling interests owners | (5,504) | (3,786) | (2,620)
Valuation allowance | (18,006) | 6,919 | 10,036
Tax credits | (349) | (1,258) | (551)
Tax rate change | 19,545 | 0 | 0
Return to provision | (62) | 400 | 0
Earn-out liability | 460 | 433 | 0
Equity compensation | (1,371) | 0 | 0
Other permanent differences | 92 | 56 | 15
Total tax expense | $ 118 | $ 88 | $ 7
Effective Income Tax Rate Reconciliation, Percent [Abstract] |  |  |
Tax expense (benefit) at the U.S. federal statutory rate | 34.99843% | 35.00% | 35.00%
State tax based on income, net of refunds and federal benefits | (1.70%) | 1.50% | 5.00%
Taxes on subsidiaries’ and joint ventures’ earnings allocated to noncontrolling interests owners | (34.50%) | 51.70% | 15.30%
Valuation allowance | (113.00%) | (94.50%) | (58.40%)
Tax credits | (2.20%) | 17.20% | 3.20%
Tax rate change | 122.70% | 0.00% | 0.00%
Return to provision | (0.40%) | (5.50%) | 0.00%
Earn-out liability | 2.90% | (5.90%) | 0.00%
Equity compensation | (8.60%) | (0.00%) | (0.00%)
Other permanent differences | 0.60% | (0.80%) | (0.10%)
Effective income rate, percent | 0.80% | (1.30%) | 0.00%

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