Credit Agreement (Details) (USD $)			1 Months Ended
	Jun. 30, 2014 Credit Agreement	Jun. 30, 2014 China Credit Agreement	Aug. 11, 2014 China Credit Agreement Subsequent Event	Aug. 11, 2014 Mortgage Subsequent Event
Notes Payable and Long-Term Debt
Outstanding borrowings	$ 0	$ 3,200,000	$ 8,100,000
Outstanding letters of credit	100,000
Amount unused balance under the Credit Agreement	399,900,000
Current borrowing capacity	256,300,000
Effective interest rate on debt		6.00%		4.928%
Increase in borrowings			4,900,000
Loan amortization period				30 years
Gross amount of mortgage				$ 33,900,000
Term of mortgage loan				15 years
Asset coverage ratio per debt covenant				1.10
Debt covenant ratio for earnings, EBITDA, and annual rental expense				2.25