Debt (Summary of Debt) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Line of Credit Facility [Line Items]
Total debt	$ 152,908	$ 215,500
Less: Debt, current portion	17,158	10,000
Debt, net of current portion	135,750	205,500
Effective interest rate	2.14%	2.88%
Revolving Credit Loans [Member]
Line of Credit Facility [Line Items]
Total debt	70,408	123,000
Effective interest rate	1.95%	2.68%
Term Loans [Member]
Line of Credit Facility [Line Items]
Total debt	82,500	92,500
Effective interest rate	2.39%	3.14%
Short-term Debt [Member]
Line of Credit Facility [Line Items]
Less: Debt, current portion	17,158	10,000
Effective interest rate	2.39%	3.14%
Long-term Debt [Member]
Line of Credit Facility [Line Items]
Debt, net of current portion	$ 135,750	$ 205,500
Effective interest rate	2.11%	2.86%