Summary of Significant Accounting Policies (Tax Cuts and Jobs Act) (Details 2) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended
	Dec. 31, 2017	Mar. 31, 2018	Jun. 30, 2018
Accounting Policies [Abstract]
Provisional income tax expense	$ 3.6	$ 0.1
Low income housing investment partnerships basis adjustments, provision income tax expense		$ 2.0	$ 2.0