Pension and Profit Sharing Plans - Breakdown by Level (Detail) $ in Thousands	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	$ 8,781
Money Market Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	87
Obligations of State and Political Subdivisions [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	208
Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	449
Mortgage-backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	901
Corporate Stocks and Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	7,136
Level 1 Inputs [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	7,223
Level 1 Inputs [Member] | Money Market Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	87
Level 1 Inputs [Member] | Corporate Stocks and Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	7,136
Level 2 Inputs [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	1,558
Level 2 Inputs [Member] | Obligations of State and Political Subdivisions [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	208
Level 2 Inputs [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	449
Level 2 Inputs [Member] | Mortgage-backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value	$ 901