Credit Facilities and Restricted Cash (Details) € in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2015 EUR (€)
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	$ 54,700,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity	100,000,000
Line of credit facility, additional borrowing capacity	50,000,000
Line of credit facility, maximum borrowing capacity	150,000,000
Credit Facility, Subfacility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity	$ 50,000,000
Credit Agreement [Member]
Line of Credit Facility [Line Items]
Line of credit facility, expiration date	Apr. 01, 2016
Line of credit facility, commitment fee description	The Credit Agreement contains quarterly commitment fees that vary based on borrowings outstanding.
Line of credit facility, interest rate description	The revolving loans under the Credit Agreement will generally bear interest, at our option, at either (i) the alternate base rate, which is defined as a rate per annum equal to the higher of (a) the Prime Rate in effect on such day, (b) the Federal Funds Effective Rate in effect on such day plus 1/2 of 1%, and (c) the LIBOR for an Interest Period of one month plus 1.50%, or (ii) a floating per annum rate based on LIBOR (based on one, two, three or six-month interest periods) plus a margin equal to between 1.50% and 2.50%, depending on our leverage ratio as of the fiscal quarter most recently ended. A default interest rate shall apply on all obligations during an event of default under the Credit Agreement, at a rate per annum equal to 2.00% above the applicable interest rate.
Line of credit facility, revolving credit, description	Revolving loans may be borrowed, repaid and reborrowed and voluntarily prepaid at any time without premium or penalty.
Line of credit facility, collateral	The obligations under the Credit Agreement are guaranteed by our present and future material domestic subsidiaries. In addition, obligations outstanding under the Credit Agreement are secured by substantially all of our assets and the assets of our material domestic subsidiaries.
Line of credit facility, covenant terms	The Credit Agreement contains customary covenants for a credit facility of this size and type, that include, among others, covenants that limit our ability to incur indebtedness, create liens, merge or consolidate, dispose of assets, make investments, enter into swap agreements, pay dividends or make distributions, enter into transactions with affiliates, enter into restrictive agreements and enter into sale and leaseback transactions. The Credit Agreement provides for financial covenants that require us to maintain a minimum interest coverage ratio and limit the maximum leverage that we can maintain at any one time.
Line of credit facility, amount outstanding	$ 0
Debt Instrument, Default Interest Rate	2.00%	2.00%
Credit Agreement [Member] | Federal Funds Effective Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Credit Agreement [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Credit Agreement [Member] | LIBOR Plus Rate Based on Leverage Ratio [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Credit Agreement [Member] | LIBOR Plus Rate Based on Leverage Ratio [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.50%
HSBC Credit Facility [Domain]
Line of Credit Facility [Line Items]
Line of credit facility, current borrowing capacity | €		€ 25.0
Bank Acceptances Executed and Outstanding	$ 12,500,000