Debt (Details) € in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 USD ($)	Sep. 29, 2017 USD ($)	Sep. 28, 2017 USD ($)	Jun. 30, 2017 AUD	May 31, 2017 AUD
Current portion [Abstract]
Short-term borrowings		$ 0			$ 1,937
Short-term borrowings and current portion of long-term debt		1,105			10,835
Long-term portion [Abstract]
Long-term debt, net		436,937			508,815
Total debt		438,042			519,650
Debt
Standby Letters of Credit					$ 4,200
Average total leverage ratio, dividend declarations				300.00%	300.00%
Maximum average total leverage ratio, share repurchases				250.00%	250.00%
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	$ 4,883	4,814
Financing costs deferred	1,104	69	$ 320
Write-off of fully amortized deferred financing costs	(1,381)	0
Balance at end of year	$ 4,606	4,883	$ 4,814
Less: Accumulated amortization		(3,771)			$ (2,982)
Deferred financing costs, net of accumulated amortization		1,112			1,624
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	1.025%
Debt Instrument, Interest Rate Margins on Variable Rate, Maximum	1.425%
Base Rate [Member]
Debt
Debt Instrument, Interest Rate Margins on Variable Rates, Minimum	0.025%
Debt Instrument, Interest Rate Margins on Variable Rate, Maximum	0.425%
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		354,549			410,439
Debt
Line of credit facility facility, maximum borrowing capacity						$ 750,000	$ 465,000
Line of credit facility, term (in years)	5 years
Line of Credit, Accordian Feature Increase in borrowing capacity					75,000
Line of Credit Facility, Maximum Capacity Including Accordian					825,000
Line of Credit Facility, Amount Outstanding					410,439
Line of credit facility, remaining borrowing capacity					$ 335,361
Weighted average effective interest rate (in hundredths)				2.90%	2.90%
Annual facility fee, minimum (in hundredths)	0.10%
Annual facility fee, maximum (in hundredths)	0.20%
Receivables Securitization Facility [Member]
Long-term portion [Abstract]
Receivable Securitization Facility		83,500			$ 100,000
Debt
Receivables Facility, Borrowing Capacity Peak Seasonal Maximum					255,000
Receivables Facility, Borrowing Capacity NonSeasonal Minimum					80,000
Receivables Facility, Borrowing Capacity NonSeasonal Maximum					220,000
Receivables Facility, Term (in years)	2 years
Receivable Securitization Facility		83,500			$ 100,000
Weighted average effective interest rate				2.30%	2.30%
Receivables facility, unused fee	0.35%
Australian Seasonal Credit Facility [Member]
Current portion [Abstract]
Australian credit facility		$ 1,105			$ 8,898
Debt
Line of credit facility facility, maximum borrowing capacity | AUD								AUD 20,000,000	AUD 3,000,000
Bank Overdrafts [Member]
Debt
Borrowing Capacity, Bank Overdraft Facility (in Euros) | €				€ 12,000