Employee Benefit Plans - Fair Value of Pension Plan Assets by Asset Category (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	$ 2,897	$ 2,820
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	4	3
Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	1,139	1,070
Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	1,754	1,747
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	2,897	2,820
Fair Value, Inputs, Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	4	3
Fair Value, Inputs, Level 1 | Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	1,139	1,070
Fair Value, Inputs, Level 1 | Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Cash and cash equivalents	$ 1,754	$ 1,747