Debt and Other Borrowings - Carrying Amounts and Fair Values of Debt Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
5.5% Senior Notes due in 2026 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate	5.50%
Carrying Amount
Debt Instrument [Line Items]
Long-term debt, fair value	$ 348.9	$ 356.7
Carrying Amount | Other borrowings
Debt Instrument [Line Items]
Long-term debt, fair value	2.9	11.1
Carrying Amount | 5.5% Senior Notes due in 2026 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, fair value	346.0	345.6
Fair Value
Debt Instrument [Line Items]
Long-term debt, fair value	359.9	355.3
Fair Value | Other borrowings
Debt Instrument [Line Items]
Long-term debt, fair value	2.9	11.1
Fair Value | 5.5% Senior Notes due in 2026 | Senior Notes
Debt Instrument [Line Items]
Long-term debt, fair value	$ 357.0	$ 344.2