Organization and Basis of Presentation (Details)
1 Months Ended 3 Months Ended 6 Months Ended
Nov. 30, 2013
shares
Apr. 30, 2012
USD ($)
shares
Jun. 30, 2017
USD ($)
state
Jun. 30, 2016
USD ($)
Jun. 30, 2017
USD ($)
state
Jun. 30, 2016
USD ($)
Business Acquisition [Line Items]            
Proceeds from issuance of common stock, net of stock issuance costs   $ 510,000,000        
Number of states in which the entity operates | state     50   50  
Deferred policy acquisition cost, amortization expense     $ 1,300,000 $ 1,300,000 $ 2,300,000 $ 2,200,000
Premium deficiency reserve     $ 0 $ 0 $ 0 $ 0
Common Stock - Class A            
Business Acquisition [Line Items]            
Stock issued during period, shares, net issues (in shares) | shares   55,000,000        
MAC Financial Holding Corporation and Subsidiaries            
Business Acquisition [Line Items]            
Consideration transferred, cash and equity interests issued and issuable   $ 8,500,000        
Consideration transferred, liabilities incurred   $ 1,300,000        
IPO            
Business Acquisition [Line Items]            
Stock issued during period, shares, net issues (in shares) | shares 2,400,000