Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Tax Cuts and Jobs Act (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended |
---|---|---|
Mar. 31, 2018 |
Dec. 31, 2017 |
|
Income Taxes [Line Items] | ||
Income Tax Benefit, Continuing Operations, Adjustment of Deferred Tax Asset | $ (0.4) | |
U.S. Internal Revenue Service (IRS) [Member] | ||
Income Taxes [Line Items] | ||
Effective income tax rate, percent | 34.00% | |
Scenario, Forecast [Member] | U.S. Internal Revenue Service (IRS) [Member] | ||
Income Taxes [Line Items] | ||
Effective income tax rate, percent | 21.00% |