Employee Benefits Plans (Detail) - Amount recognized in the consolidated balance sheet (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Current liabilities	$ (161)	$ (162)
Non current liabilities	(2,046)	(1,903)
Total	(2,207)	(2,065)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Current liabilities	(184)	(208)
Non current liabilities	(1,171)	(1,192)
Total	$ (1,355)	$ (1,400)