Employee Benefit Plans - Balances of the Plan Assets, by Fair Value Hierarchy Level (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	$ 123,188,000	$ 108,859,000	$ 101,383,000
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	2,985,000	4,396,000
Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	118,000	207,000
Collateralized Mortgage Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	245,000	208,000
Municipal Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	1,112,000	910,000
Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	2,363,000	2,588,000
Strategic Income Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	3,985,000
Taxable Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	3,970,000
Fixed Income Funds Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	13,834,000	12,600,000
Fixed Income Funds Alternative [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	6,131,000	6,116,000
Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	195,000	209,000
Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	20,089,000	14,712,000
Equity Mutual Funds Domestic Equity Large Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	23,042,000	19,172,000
Equity Mutual Funds Domestic Equity Mid Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	5,540,000	2,552,000
Equity Mutual Funds Domestic Equity Small Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	15,293,000	10,688,000
Equity Mutual Funds International Emerging Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	6,076,000	5,241,000
Equity Mutual Funds International Equity Developed [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	11,817,000	4,158,000
Equity Mutual Funds Alternative Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	5,692,000	6,727,000
Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	701,000	726,000
Fixed Income Funds General [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		12,463,000
Equity Mutual Funds Global Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		5,186,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	118,649,000	106,446,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	2,985,000	4,396,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Collateralized Mortgage Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Municipal Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	2,226,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Strategic Income Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	3,985,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Taxable Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	3,970,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Funds Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	13,834,000	12,600,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Funds Alternative [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	6,131,000	6,116,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	195,000	209,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	20,089,000	14,712,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds Domestic Equity Large Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	23,042,000	19,172,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds Domestic Equity Mid Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	5,540,000	2,552,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds Domestic Equity Small Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	15,293,000	10,688,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds International Emerging Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	6,076,000	5,241,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds International Equity Developed [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	11,817,000	4,158,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds Alternative Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	5,692,000	6,727,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed Income Funds General [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		12,463,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Equity Mutual Funds Global Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		5,186,000
Significant Other Observable Inputs (Level 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	4,539,000	2,413,000
Significant Other Observable Inputs (Level 2) [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	118,000	207,000
Significant Other Observable Inputs (Level 2) [Member] | Collateralized Mortgage Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	245,000	208,000
Significant Other Observable Inputs (Level 2) [Member] | Municipal Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	1,112,000	910,000
Significant Other Observable Inputs (Level 2) [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	2,363,000	362,000
Significant Other Observable Inputs (Level 2) [Member] | Strategic Income Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0
Significant Other Observable Inputs (Level 2) [Member] | Fixed Income Funds Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fixed Income Funds Alternative [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds Domestic Equity Large Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds Domestic Equity Mid Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds Domestic Equity Small Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds International Emerging Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds International Equity Developed [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds Alternative Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	701,000	726,000
Significant Other Observable Inputs (Level 2) [Member] | Fixed Income Funds General [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		0
Significant Other Observable Inputs (Level 2) [Member] | Equity Mutual Funds Global Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		0
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Collateralized Mortgage Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Municipal Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Strategic Income Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0
Significant Unobservable Inputs (Level 3) [Member] | Fixed Income Funds Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fixed Income Funds Alternative [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds Domestic Equity Large Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds Domestic Equity Mid Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds Domestic Equity Small Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds International Emerging Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds International Equity Developed [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds Alternative Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fixed Income Funds General [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		0
Significant Unobservable Inputs (Level 3) [Member] | Equity Mutual Funds Global Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset at fair value		$ 0