Organization and Basis of Presentation - Accounting Standards Adopted (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Jan. 01, 2019
Accounting Standards Adopted in 2019
Recognized lease liability on consolidated balance sheet	$ 45.6
Right-of-use asset on consolidated balance sheet	$ 46.1
Practical expedient, ASU No. 2016-02	true
ASU 2016-02
Accounting Standards Adopted in 2019
Recognized lease liability on consolidated balance sheet			$ 50.3
Right-of-use asset on consolidated balance sheet			$ 50.6
ASU 2018-15
Accounting Standards Adopted in 2019
Change in Accounting Principle, Accounting Standards Update, Early Adoption [true false]			true
Hosting arrangements that are service contracts	$ 6.3
ASU 2016-13
Accounting Standards Adopted in 2019
Percentage of estimated increase in ACL and the reserve for unfunded commitments	15.00%	10.00%
Allocation period, impact Of adoption of ASU	3 years