Derivative Instruments And Hedging Activities (Narrative) (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Derivative Instruments And Hedging Activities [Line Items]
Notional value of foreign exchange contracts	$ 171,000,000	$ 178,000,000
Net cash outflow/inflow from settlement of derivative contracts	7,700,000	5,800,000
Derivatives Assets	553,000	2,617,000
Derivatives Liabilities	$ 947,000	$ 172,000