Pension, Profit Sharing, and Other Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule Of Pension Profit Sharing and Other Employee Benefit Plan [Line Items]
Expected rate of return on assets	4.00%	4.50%	4.50%
Maximum Percentage Of Asset Allocated To Controll Market Volatility	more than 60
Maximum Percentage Of Market Value For Initial Acquisition Of Equity Portion	not exceed 5
Minimum Percentage Of Value Of Equity Portion For Sale	exceeds 10
Maximum Percentage Of Corporate Debt Issuable To Single Issuer	not exceed 10
Four Zero One K Provision Description	The 401(k) provision is voluntary and covers all eligible employees after ninety days of service. Employees contributing to the 401(k) provision receive a matching contribution of 100% of the first 3% of compensation and 50% of the next 2% of compensation subject to employee contribution limitations. The Company matching contribution vests immediately.
Profit Sharing and Matching Contribution		$ 1.5	$ 1.4	$ 1.4
Executive Incentive Retirement Plan Benefit Cost	$ 0.2	$ 0.3	$ 0.2
Equity Securities [Member]
Schedule Of Pension Profit Sharing and Other Employee Benefit Plan [Line Items]
Current target allocations for plan assets minimum	0.00%
Current target allocations for plan assets maximum	60.00%
Fixed Income Securities
Schedule Of Pension Profit Sharing and Other Employee Benefit Plan [Line Items]
Current target allocations for plan assets minimum	0.00%
Current target allocations for plan assets maximum	100.00%
Cash Funds And Emerging Market Debt Funds
Schedule Of Pension Profit Sharing and Other Employee Benefit Plan [Line Items]
Current target allocations for plan assets minimum	0.00%
Current target allocations for plan assets maximum	100.00%