Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization expense	$ 5.4	$ 6.1	$ 6.0
Insurance license [Member] | Workmen's Auto Insurance Company [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 1.4