Effect of Derivative Financial Instruments on Income Statement (Detail) (Interest rate contracts, USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Not Designated as Hedging Instrument \| Other Income
Derivative [Line Items]
Amount of Gain (Loss) Recognized Income on Derivative	$ 66	$ 3
Designated as Hedging Instrument \| Cash Flow Hedging
Derivative [Line Items]
Amount of Gain Recognized in Ohter Comprehensive Income on Derivative (Effective Portion)	297	467
Designated as Hedging Instrument \| Cash Flow Hedging \| Interest expense
Derivative [Line Items]
Amount of Loss Reclassified from Other Comprehensive Income into Income (Effective Portion)	$ 188

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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