Summary of Significant Accounting Policies Leases (Details) $ in Millions	1 Months Ended
	Jan. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2019 USD ($) land_easement
Leases [Abstract]
Impairment losses recorded upon adoption of ASU 2016-02	$ 0.0
Number of land easements treated as leases upon adoption of ASU 2016-02 | land_easement			0
Operating lease right of use assets		$ 41.4	$ 49.0
Operating lease liabilities		$ 41.4	$ 48.8
Finance lease expense impact of adoption of ASU 2016-02	$ 0.0