Goodwill and Other Intangible Assets (Goodwill and Impairment) (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 469,433,000	$ 469,433,000
Number of operating segments | segment	3
Period for which the company provided a net income projection under the income approach to determine the fair value of the reporting units	3 years
Goodwill impairment	$ 0