New Accounting Pronouncements (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Jan. 01, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification as a charge to retained earnings	$ 2.5
Percentage of total revenue, percentage	2.00%
Accounting Standards Update 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of change in accounting principle, net of tax (See Note 2)		$ 4.4