Debt (Details) € in Thousands, AUD in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 EUR (€)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 AUD
Long-term portion [Abstract]
Total debt		$ 320,838			$ 329,715
Gain on cash flow hedge ineffectiveness	$ 585
Cumulative fair value of de-designated cash flow hedges, gross					3,665
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	$ 4,493	4,099
Financing costs deferred	320	394	$ 1,044
Write-off fully amortized deferred financing costs	0	0
Balance at end of year	4,813	4,493	4,099
Accumulated amortization of deferred financing costs [Abstract]
Balance at beginning of year	(2,527)	(1,985)
Amortization of deferred financing costs	(617)	(542)
Write Off Of Accumulated Amortized Deferred Financing Costs	0	0
Balance at end of year	$ (3,144)	(2,527)	$ (1,985)
Deferred financing costs, net of accumulated amortization		1,966			1,669
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		251,709			273,015
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					273,015
Line of credit facility, remaining borrowing capacity					$ 187,985
Weighted average effective interest rate (in hundredths)				2.00%	2.00%	2.00%
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		67,600			$ 55,000
Debt
Receivables Facility, Borrowing Capacity Peak Seasonal Maximum					200,000
Receivables Facility, Borrowing Capacity NonSeasonal Minimum					55,000
Receivables Facility, Borrowing Capacity NonSeasonal Maximum					135,000
Receivables Facility, Term (in years)	2 years
Receivable Securitization Facility		67,600			$ 55,000
Weighted average effective interest rate				1.20%	1.20%	1.20%
Receivables facility, unused fee	0.35%
Australian Seasonal Credit Facility [Member]
Current portion [Abstract]
Other Long-term Debt, Current		$ 1,529			$ 1,700
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) | €				€ 5,000