Long-term Debt Outstanding Revolving Loans (Details) - Revolving credit facility [Member] € in Thousands, £ in Thousands, CAD in Thousands, $ in Thousands	Dec. 31, 2016 GBP (£)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 EUR (€)	Dec. 31, 2016 CAD
British pound (Swingline Loan) [Member] [Member]
Line of Credit Facility [Line Items]
Long-term Debt, Gross	£ 1,000	$ 1,234
Debt Instrument, Interest Rate, Stated Percentage	2.48%	2.48%	2.48%	2.48%
British pound [Member]
Line of Credit Facility [Line Items]
Long-term Debt, Gross	£ 37,000	$ 45,651
Debt Instrument, Interest Rate, Stated Percentage	2.26%	2.26%	2.26%	2.26%
Canadian dollar [Member]
Line of Credit Facility [Line Items]
Long-term Debt, Gross		$ 7,821		CAD 10,500
Debt Instrument, Interest Rate, Stated Percentage	2.93%	2.93%	2.93%	2.93%
Euro [Member]
Line of Credit Facility [Line Items]
Long-term Debt, Gross		$ 26,282	€ 24,900
Debt Instrument, Interest Rate, Stated Percentage	2.00%	2.00%	2.00%	2.00%