Basis and Summary of Significant Accounting Policies - Supplemental Disclosure of Noncash Investing Transactions (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2019 |
Mar. 31, 2018 |
|
| Accounting Policies [Abstract] | ||
| Asset acquisition, fair value of non-cash consideration | $ 0.4 | |
| Asset acquisition, non-cash settlement of accounts receivable | $ 0.1 | $ 0.2 |