Pension, Profit Sharing, and Other Employee Benefit Plans (Additional Information) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Pension Profit Sharing and Other Employee Benefit Plan [Line Items]
Expected return on plan assets	6.00%	5.50%	4.00%
Maximum Percentage Of Asset Allocated To Control Market Volatility	more than 70%
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	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	$ 1.8	$ 1.7	$ 1.5
Executive Incentive Retirement Plan Benefit Cost	$ 0.4	$ 0.3	$ 0.2
Equity Securities
Schedule Of Pension Profit Sharing and Other Employee Benefit Plan [Line Items]
Current target allocations for plan assets minimum	50.00%
Current target allocations for plan assets maximum	70.00%
Fixed Income Securities
Schedule Of Pension Profit Sharing and Other Employee Benefit Plan [Line Items]
Current target allocations for plan assets minimum	30.00%
Current target allocations for plan assets maximum	40.00%
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	10.00%