Fair Value of Financial Instruments - Assets Measured at Fair Value Using Level 3 (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair Value Disclosures [Abstract]
Beginning Balance	$ 2,037	$ 1,953	$ 2,126
Transfers into level 3
Transfers out of level 3			(25)
Purchases, sales issuances and settlements	(1,090)	(50)	(25)
Unrealized gains (losses) included in accumulated loss	341	134	(123)
Ending Balance	$ 1,288	$ 2,037	$ 1,953