Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financial assets and liabilities measured on a recurring basis at fair value
Mutual fund assets	$ 15,425	$ 14,093
Derivative assets:
Foreign currency contracts	10	67
Total assets at fair value	15,435	14,160
Derivative liabilities:
Foreign currency contracts	15	2
Interest rate contracts	43	57
Total liabilities at fair value	58	59
Level 1 [Member]
Financial assets and liabilities measured on a recurring basis at fair value
Mutual fund assets	15,425	14,093
Derivative assets:
Foreign currency contracts
Total assets at fair value	15,425	14,093
Derivative liabilities:
Foreign currency contracts
Interest rate contracts
Total liabilities at fair value
Level 2 [Member]
Financial assets and liabilities measured on a recurring basis at fair value
Mutual fund assets
Derivative assets:
Foreign currency contracts	10	67
Total assets at fair value	10	67
Derivative liabilities:
Foreign currency contracts	15	2
Interest rate contracts	43	57
Total liabilities at fair value	58	59
Level 3 [Member]
Financial assets and liabilities measured on a recurring basis at fair value
Mutual fund assets
Derivative assets:
Foreign currency contracts
Total assets at fair value
Derivative liabilities:
Foreign currency contracts
Interest rate contracts
Total liabilities at fair value