Recent Authoritative Accounting Guidance - New Accounting Pronouncements and Changes in Accounting Principles (Details) - USD ($) $ in Millions |
12 Months Ended | |
---|---|---|
Dec. 31, 2018 |
Dec. 31, 2016 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Reduction in income tax expense | $ 0.0 | |
Accounting Standards Update 2016-02 [Member] | ||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Operating Lease, Right-of-Use Asset | $ 54.6 | |
Operating Lease, Liability | 54.6 | |
Accounting Standards Update 2018-02 | Adjustments for New Accounting Principle, Early Adoption | ||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings | $ 3.1 |