Derivatives and Other Financial Instruments - Narrative (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Derivative [Line Items]
Cumulative net after-tax gain related to net investment hedges	$ 3,700,000		$ 3,900,000
Net after-tax unrealized gain included in accumulated AOCI expected to be transferred	100,000		(100,000)
Gain (loss) on fair value hedge derivatives	(300,000)	(500,000)
Foreign Exchange Forward Contracts [Member]
Derivative [Line Items]
Amount of Loss Recognized in AOCI on Derivative (Effective Portion)	$ 184,000	$ (507,000)