Employee Benefit Plans - Fair Value of Total Plan Assets by Major Asset Category (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	$ 76,710	$ 64,390	$ 58,839
(Level 1) Quoted Prices in Active Markets for Identical Assets [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	76,710	64,390
(Level 2) Significant Other Observable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
(Level 3) Significant Unobservable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Cash and cash equivalents [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	934	1,078
Cash and cash equivalents [Member] | (Level 1) Quoted Prices in Active Markets for Identical Assets [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	934	1,078
Cash and cash equivalents [Member] | (Level 2) Significant Other Observable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Cash and cash equivalents [Member] | (Level 3) Significant Unobservable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Fixed income securities [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	12,596	17,318
Fixed income securities [Member] | (Level 1) Quoted Prices in Active Markets for Identical Assets [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	12,596	17,318
Fixed income securities [Member] | (Level 2) Significant Other Observable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Fixed income securities [Member] | (Level 3) Significant Unobservable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Domestic large cap [Member] | Equity securities [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	40,669	29,594
Domestic large cap [Member] | Equity securities [Member] | (Level 1) Quoted Prices in Active Markets for Identical Assets [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	40,669	29,594
Domestic large cap [Member] | Equity securities [Member] | (Level 2) Significant Other Observable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Domestic large cap [Member] | Equity securities [Member] | (Level 3) Significant Unobservable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Mid cap value/growth [Member] | Equity securities [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	12,610	9,090
Mid cap value/growth [Member] | Equity securities [Member] | (Level 1) Quoted Prices in Active Markets for Identical Assets [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	12,610	9,090
Mid cap value/growth [Member] | Equity securities [Member] | (Level 2) Significant Other Observable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Mid cap value/growth [Member] | Equity securities [Member] | (Level 3) Significant Unobservable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Small cap value/growth [Member] | Equity securities [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	7,163	5,137
Small cap value/growth [Member] | Equity securities [Member] | (Level 1) Quoted Prices in Active Markets for Identical Assets [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	7,163	5,137
Small cap value/growth [Member] | Equity securities [Member] | (Level 2) Significant Other Observable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Small cap value/growth [Member] | Equity securities [Member] | (Level 3) Significant Unobservable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Foreign equities [Member] | Equity securities [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	2,738	2,173
Foreign equities [Member] | Equity securities [Member] | (Level 1) Quoted Prices in Active Markets for Identical Assets [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	2,738	2,173
Foreign equities [Member] | Equity securities [Member] | (Level 2) Significant Other Observable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	0	0
Foreign equities [Member] | Equity securities [Member] | (Level 3) Significant Unobservable Inputs [Member]
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of plan assets	$ 0	$ 0