Financial Instruments Foreign Exchange Summary (Details) (Not Designated as Hedging Instrument [Member], Foreign currency financial instruments [Member])
In Thousands, unless otherwise specified
Dec. 31, 2012
USD ($)
Dec. 31, 2011
USD ($)
Sep. 30, 2011
USD ($)
Dec. 31, 2010
USD ($)
Dec. 31, 2012
Japanese Yen
USD ($)
Dec. 31, 2012
Japanese Yen
JPY (¥)
Dec. 31, 2011
Japanese Yen
USD ($)
Dec. 31, 2011
Japanese Yen
JPY (¥)
Dec. 31, 2012
Pound Sterling
USD ($)
Dec. 31, 2012
Pound Sterling
GBP (£)
Dec. 31, 2011
Pound Sterling
USD ($)
Dec. 31, 2011
Pound Sterling
GBP (£)
Derivative [Line Items]                        
Carrying amount $ 24,742 [1] $ 23,736 $ 23,736 [1] $ 137,823 $ 1,695   $ 1,899   $ 23,047   $ 21,837  
Notional amount           ¥ 146,991   ¥ 146,241   £ 14,186   £ 14,055
[1] The financial instruments payable in foreign currencies are entered into with a counterparty and are considered Level 2 measurements. Carrying value approximates fair value.