Summary of Business and Significant Accounting Policies - Narrative (Details) $ in Millions |
3 Months Ended | 20 Months Ended | |
---|---|---|---|
Mar. 31, 2018
USD ($)
state
|
Mar. 31, 2017
USD ($)
|
Jun. 30, 2012
USD ($)
|
|
Accounting Policies [Abstract] | |||
Number of states in which the Company is licensed to market and sell health insurance | state | 50 | ||
Book-of-business transfers | $ 13.9 | ||
Book-of-business, margin earned | $ 0.6 | $ 0.5 |