Commitments, Contingencies and Guarantees (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Payment Required Upon Termination Of Employment [Line Items]
Rent expense charged to operations	$ 25,200,000	$ 23,000,000	$ 22,700,000
Minimum royalty payments due through 2035	2,100,000
Minimum purchase commitments	8,400,000
Loss contingency, range of possible loss, maximum	2,500,000	2,500,000	2,600,000
Outstanding letters of credit to insurance company as security for workers' compensation claims	$ 1,300,000
Period for continued vesting of outstanding equity awards upon termination of CEO without cause other than following a change in control, years	two years
Total contingent liabilities	$ 3,500,000	3,000,000
Liabilities for indemnification obligations	0	0
Payment required to CEO upon termination of employment without cause other than following change in control
Payment Required Upon Termination Of Employment [Line Items]
Employee agreement contingencies	1,600,000
Payment required to officers upon termination of employment following change of control
Payment Required Upon Termination Of Employment [Line Items]
Employee agreement contingencies	31,900,000
Employee healthcare insurance policy
Payment Required Upon Termination Of Employment [Line Items]
Retained claim liability per incident	1,000,000	1,000,000	450,000
General insurance expense	52,700,000	47,200,000	40,400,000
Estimated liability for healthcare claims	4,800,000	4,200,000
Workers compensation insurance policy
Payment Required Upon Termination Of Employment [Line Items]
Retained claim liability per incident	$ 300,000	$ 300,000	$ 300,000