Other Assets (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Deferred tax assets, valuation allowance, current	$ 0.0	$ 0.0
State and Local Jurisdiction [Member]
Operating loss carryforwards	$ 7.2
Minimum [Member] | State and Local Jurisdiction [Member]
Operating loss carryforwards, expiration date	Dec. 31, 2026
Maximum [Member] | State and Local Jurisdiction [Member]
Operating loss carryforwards, expiration date	Dec. 31, 2034