Annual report pursuant to Section 13 and 15(d)

Income Taxes - Reconciliation of The Statutory Federal Rate and The Company's Effective Tax Rate (Details)

v3.8.0.1
Income Taxes - Reconciliation of The Statutory Federal Rate and The Company's Effective Tax Rate (Details)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]      
Tax provision (benefit) at federal statutory rate (34.00%) (34.00%) (34.00%)
State income taxes, net of federal benefit 2.42% 1.92% 0.87%
Effect of noncontrolling and redeemable noncontrolling interests 54.92% 50.23% 29.53%
Stock-based compensation (0.75%) (0.68%) (1.06%)
Effect of prepaid tax asset (0.00%) (5.57%) 0.04%
Tax credits (1.36%) (1.61%) (0.43%)
Effect of federal rate change (12.53%) (0.00%) (0.00%)
Effect of valuation allowance 1.86% 0.25% (0.00%)
Other 0.56% 1.56% 0.85%
Total 12.62% 13.46% (2.08%)