Derivative Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Notional amounts of foreign currency forward contracts	$ 121,930	$ 129,037
Swedish Kronor
Notional amounts of foreign currency forward contracts	99,214	98,385
Currency Euro [Member]
Notional amounts of foreign currency forward contracts	265	2,232
Currency British Pound Sterling [Member]
Notional amounts of foreign currency forward contracts	5,641	15,619
Australian Dollar
Notional amounts of foreign currency forward contracts	5,986	7,022
Japan, Yen
Notional amounts of foreign currency forward contracts	4,462	5,157
Other
Notional amounts of foreign currency forward contracts	$ 6,362	$ 622