Intangible Assets (Narrative) (Details) - USD ($)	Mar. 31, 2016	Dec. 31, 2015	[1]	Mar. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Gross carrying amount of other intangible assets	$ 72,300,000
Intangible assets accumulated amortization	47,400,000
Future Amortization Expense, Remainder of Fiscal Year	3,900,000
Estimated aggregate amortization expense, Year 2017	4,900,000
Estimated aggregate amortization expense, Year 2018	4,700,000
Estimated aggregate amortization expense, Year 2019	4,500,000
Estimated aggregate amortization expense, Year 2020	1,700,000
Estimated aggregate amortization expense, Year 2021	1,600,000
Goodwill [Line Items]
Goodwill	191,307,000	$ 191,307,000		$ 145,932,000	$ 145,932,000
Non Strategic [Member]
Goodwill [Line Items]
Gross goodwill	200,000,000
Accumulated impairments	114,100,000
Accumulated divestiture related write-offs	85,900,000
Goodwill	$ 0

[1] The increase in goodwill was related to the TAF acquisition in fourth quarter 2015.