Intangible Assets (Textual) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Net amortization expense of intangible assets and liabilities	$ 42.4	$ 24.0	$ 23.7