Pension and Profit Sharing Plans - Net Periodic Pension Cost (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Service cost - benefits earned during the period
Interest cost on projected benefit obligation	1,113	1,139	1,159
Expected return on plan assets	(1,140)	(1,220)	(1,092)
Amortization of unrecognized net loss	659	434	416
Net periodic pension cost	$ 632	$ 353	$ 483