Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	[1]	Jun. 30, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Gross carrying amount of other intangible assets	$ 72,300
Intangible assets accumulated amortization	48,700
Future Amortization Expense, Remainder of Fiscal Year	2,600
Estimated aggregate amortization expense, Year 2017	4,900
Estimated aggregate amortization expense, Year 2018	4,700
Estimated aggregate amortization expense, Year 2019	4,500
Estimated aggregate amortization expense, Year 2020	1,700
Estimated aggregate amortization expense, Year 2021	1,600
Goodwill [Line Items]
Goodwill	191,307	$ 191,307		$ 145,932	$ 145,932
Non Strategic [Member]
Goodwill [Line Items]
Gross goodwill	200,000
Accumulated impairments	114,100
Accumulated divestiture related write-offs	85,900
Goodwill	$ 0

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