Pension and Profit Sharing Plans - Breakdown by Level (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	$ 21,110
Money market fund [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	513
Obligations of state and political subdivisions [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	708
Corporate bonds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	1,833
Mortgage-backed securities [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	1,018
Corporate stocks and mutual funds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	17,038
Level 1 Inputs [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	17,551
Level 1 Inputs [Member] | Money market fund [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	513
Level 1 Inputs [Member] | Obligations of state and political subdivisions [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 1 Inputs [Member] | Corporate bonds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 1 Inputs [Member] | Mortgage-backed securities [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 1 Inputs [Member] | Corporate stocks and mutual funds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	17,038
Level 2 Inputs [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	3,559
Level 2 Inputs [Member] | Money market fund [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 2 Inputs [Member] | Obligations of state and political subdivisions [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	708
Level 2 Inputs [Member] | Corporate bonds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	1,833
Level 2 Inputs [Member] | Mortgage-backed securities [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value	1,018
Level 2 Inputs [Member] | Corporate stocks and mutual funds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 3 Inputs [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 3 Inputs [Member] | Money market fund [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 3 Inputs [Member] | Obligations of state and political subdivisions [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 3 Inputs [Member] | Corporate bonds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 3 Inputs [Member] | Mortgage-backed securities [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value
Level 3 Inputs [Member] | Corporate stocks and mutual funds [Member]
Pension And Profit Sharing Plans [Line Items]
Total Fair Value