Debt (Australian NAB Corporate Term Loan And Revolver) (Narrative) (Details) $ in Thousands, AUD in Millions		12 Months Ended
	Dec. 23, 2015 AUD	Dec. 31, 2016 USD ($)	Dec. 23, 2015 USD ($)
Debt Instrument [Line Items]
Amortization of debt discount	AUD 2.0
Notes payable | $		$ 148,535
Bank Guarantee Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	AUD 5.0		$ 3,600
Facility fee	1.90%
NAB Australian Corporate Term Loan And Revolver Tier 1 [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	AUD 61.3
Spread on variable interest rate	2.35%
NAB Australian Corporate Term Loan And Revolver Tier 2 [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	AUD 10.0
Spread on variable interest rate	1.50%
NAB Australian Corporate Term Loan And Revolver Tier 3 [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	AUD 5.0
Revolving Corporate Markets Loan Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	AUD 66.5		$ 48,100
Spread on variable interest rate	0.95%
Facility fee		0.95%
Maturity date		Jun. 30, 2019