Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Total securities available-for-sale	$ 509,425,000	$ 452,266,000
Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	234,751,000	212,066,000
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	63,774,000	57,896,000
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	48,669,000	50,623,000
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	39,052,000	10,158,000
Obligations of States and Political Subdivisions [Member]
ASSETS
Total securities available-for-sale	114,264,000	112,767,000
Marketable Equity Securities [Member]
ASSETS
Total securities available-for-sale	8,915,000	8,756,000
Fair Value Measurements, Recurring [Member]
ASSETS
Total securities available-for-sale	509,425,000	452,266,000
Trading securities held in a Rabbi Trust	2,864,000	2,223,000
Total securities	512,289,000	454,489,000
Total Assets	526,106,000	478,704,000
LIABILITIES
Total Liabilities	13,647,000	23,570,000
Fair Value Measurements, Recurring [Member] | Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	234,751,000	212,066,000
Fair Value Measurements, Recurring [Member] | Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	63,774,000	57,896,000
Fair Value Measurements, Recurring [Member] | Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	48,669,000	50,623,000
Fair Value Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	39,052,000	10,158,000
Fair Value Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
ASSETS
Total securities available-for-sale	114,264,000	112,767,000
Fair Value Measurements, Recurring [Member] | Marketable Equity Securities [Member]
ASSETS
Total securities available-for-sale	8,915,000	8,756,000
Fair Value Measurements, Recurring [Member] | Interest Rate Swaps [Member]
ASSETS
Derivative financial assets	13,698,000	23,748,000
LIABILITIES
Derivative financial liabilities	13,647,000	23,522,000
Fair Value Measurements, Recurring [Member] | Interest Rate Lock Commitments [Member]
ASSETS
Derivative financial assets	85,000	467,000
Fair Value Measurements, Recurring [Member] | Forward Sale Contracts [Member]
ASSETS
Derivative financial assets	34,000
LIABILITIES
Derivative financial liabilities		48,000
Level 1 [Member] | Fair Value Measurements, Recurring [Member]
ASSETS
Total securities available-for-sale	202,000	140,000
Trading securities held in a Rabbi Trust	2,864,000	2,223,000
Total securities	3,066,000	2,363,000
Total Assets	3,066,000	2,363,000
Level 1 [Member] | Fair Value Measurements, Recurring [Member] | Marketable Equity Securities [Member]
ASSETS
Total securities available-for-sale	202,000	140,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member]
ASSETS
Total securities available-for-sale	509,223,000	451,826,000
Total securities	509,223,000	451,826,000
Total Assets	523,040,000	476,041,000
LIABILITIES
Total Liabilities	13,647,000	23,570,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	234,751,000	212,066,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	63,774,000	57,896,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	48,669,000	50,623,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale	39,052,000	10,158,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
ASSETS
Total securities available-for-sale	114,264,000	112,767,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Marketable Equity Securities [Member]
ASSETS
Total securities available-for-sale	8,713,000	8,316,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Interest Rate Swaps [Member]
ASSETS
Derivative financial assets	13,698,000	23,748,000
LIABILITIES
Derivative financial liabilities	13,647,000	23,522,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Interest Rate Lock Commitments [Member]
ASSETS
Derivative financial assets	85,000	467,000
Level 2 [Member] | Fair Value Measurements, Recurring [Member] | Forward Sale Contracts [Member]
ASSETS
Derivative financial assets	34,000
LIABILITIES
Derivative financial liabilities		48,000
Level 3 [Member]
LIABILITIES
Total Liabilities	0	0
Level 3 [Member] | Fair Value Measurements, Recurring [Member]
ASSETS
Total securities available-for-sale		300,000
Trading securities held in a Rabbi Trust
Total securities		300,000
Total Assets		300,000
LIABILITIES
Total Liabilities
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies [Member]
ASSETS
Total securities available-for-sale
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Obligations of States and Political Subdivisions [Member]
ASSETS
Total securities available-for-sale
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Marketable Equity Securities [Member]
ASSETS
Total securities available-for-sale		300,000
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Interest Rate Swaps [Member]
ASSETS
Derivative financial assets
LIABILITIES
Derivative financial liabilities
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Interest Rate Lock Commitments [Member]
ASSETS
Derivative financial assets
Level 3 [Member] | Fair Value Measurements, Recurring [Member] | Forward Sale Contracts [Member]
ASSETS
Derivative financial assets