Contingencies, Commitments And Guarantees (Narrative) (Details) - USD ($) $ in Thousands			12 Months Ended
	Mar. 28, 2014	Jan. 24, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Oct. 13, 2016
Contingencies, Commitments And Guarantees [Line Items]
Litigation settlement	$ 1,500
Loss Contingency, Loss in Period	$ 300
Gain from settlement on TMW arbitration		$ 2,200
Aggregate notional value standby letters of credit			$ 53,612			$ 205,000
Rental expense under operating lease commitments			5,600	$ 5,900	$ 7,300
Deductible amount of policies, maximum			400
Commercial Contract [Member]
Contingencies, Commitments And Guarantees [Line Items]
Approximate commitments			$ 66,000
Minimum [Member]
Contingencies, Commitments And Guarantees [Line Items]
Letter Of Credit Maturity Term			1 month
Maximum [Member]
Contingencies, Commitments And Guarantees [Line Items]
Letter Of Credit Maturity Term			5 years