Debt (Details) € in Thousands, AUD in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 AUD
Long-term portion [Abstract]
Total debt		$ 328,045			$ 438,042
Loss on Cash Flow Hedge Ineffectiveness	$ 585
Gain on cash flow hedge ineffectiveness	$ 500
Debt
Standby Letters of Credit					4,000
Financial and other covenants [Abstract]
Financial covenants, dividend limitation as percent of preceding year's net income, maximum (in hundredths)	50.00%
Deferred financing costs [Abstract]
Balance at beginning of year	$ 4,814	4,494
Financing costs deferred	69	320	$ 394
Balance at end of year	$ 4,883	4,814	$ 4,494
Accumulated Amortization, Debt Issuance Costs		(3,144)			(3,771)
Deferred financing costs, net of accumulated amortization		1,670			1,112
London Interbank Offered Rate (LIBOR) [Member]
Debt
Debt Instrument, Basis Spread on Variable Rate	1.00%
Debt Instrument, Interest Rate Margins on Variable Rates, Minimum	1.15%
Debt Instrument, Interest Rate Margins on Variable Rate, Maximum	1.65%
Base Rate [Member]
Debt
Debt Instrument, Interest Rate Margins on Variable Rates, Minimum	0.15%
Debt Instrument, Interest Rate Margins on Variable Rate, Maximum	0.65%
Canadian Dealer Offered Rate [Member]
Debt
Debt Instrument, Basis Spread on Variable Rate	1.00%
Debt Instrument, Interest Rate Margins on Variable Rates, Minimum	1.15%
Debt Instrument, Interest Rate Margins on Variable Rate, Maximum	1.65%
Federal Funds Rate [Member]
Debt
Debt Instrument, Basis Spread on Variable Rate	0.50%
Commercial Paper [Member]
Debt
Debt Instrument, Basis Spread on Variable Rate	0.75%
Unsecured Syndicated Senior Credit Facility [Member]
Long-term portion [Abstract]
Long-term Line of Credit, Noncurrent		273,015			354,549
Debt
Line of credit facility facility, maximum borrowing capacity					465,000
Line of credit facility, term (in years)	5 years
Debt Instrument, Maturity Date	Nov. 20, 2020
Line of Credit, Accordian Feature Increase in borrowing capacity					75,000
Line of Credit Facility, Maximum Capacity Including Accordian					540,000
Line of Credit Facility, Amount Outstanding					354,548
Line of credit facility, remaining borrowing capacity					$ 110,452
Weighted average effective interest rate (in hundredths)				2.60%	2.60%	2.60%
Annual facility fee, minimum (in hundredths)	0.10%
Annual facility fee, maximum (in hundredths)	0.225%
Receivables Securitization Facility [Member]
Long-term portion [Abstract]
Receivable Securitization Facility		55,000			$ 83,500
Debt
Receivables Facility, Borrowing Capacity Peak Seasonal Maximum					220,000
Receivables Facility, Borrowing Capacity NonSeasonal Minimum					65,000
Receivables Facility, Borrowing Capacity NonSeasonal Maximum					150,000
Receivables Facility, Term (in years)	2 years
Receivable Securitization Facility		55,000			$ 83,500
Weighted average effective interest rate				1.50%	1.50%	1.50%
Receivables facility, unused fee	0.35%
Australian Seasonal Credit Facility [Member]
Current portion [Abstract]
Other Long-term Debt, Current		$ 1,700			$ 1,105
Debt
Line of credit facility facility, maximum borrowing capacity | AUD						AUD 3,000
Bank Overdrafts [Member]
Debt Instrument [Line Items]
Borrowing Capacity, Bank Overdraft Facility (in Euros) | €				€ 10,000