Employee Stock Ownership Plan - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | 12 Months Ended | |
---|---|---|---|---|
Jun. 30, 2017 |
Dec. 31, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
|
Share-based Payment Arrangement [Abstract] | ||||
Initial term of employer loan | 15 years | |||
Employer loan, annual interest rate | 3.71% | |||
Compensation Expense | $ 2.5 | $ 0.9 | $ 2.3 |