Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Intangible Assets [Abstract]
Amortization expense for acquired intangible assets	$ 3.9	$ 3.4	$ 11.5	$ 7.8