Derivative - Interest Rate Swap Agreement - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Interest Rate Derivatives Outstanding [Line Items]
Notional amount of derivative contract	$ 150,000,000
Interest rate swap fixed percentage	4.165%
Derivative instruments, gain (Loss) Reclassified from Accumulated OCI	0
Derivative, Ineffectiveness Gain (Loss)	0
Financial Instruments Owned and Pledged as Collateral	9,600,000
Financial Instruments, Owned and Pledged as Collateral, at Fair Value	9,600,000
Amount of derivative will mature within next 12 months	0
Gain loss after income tax recognized in other comprehensive income	5,200,000	4,500,000
The fair value of the derivative liability		6,900,000
Fair value of derivative assets	1,200,000
Investment securities principal amount	12,700,000
Fair value of investment securities	12,100,000
Interest Rate Swap [Member]
Interest Rate Derivatives Outstanding [Line Items]
Notional amount of derivative contract	250,000,000	115,000,000
Interest rate swap fixed percentage		2.88%
Number of interest rate swaps	4
Other comprehensive income (Loss), Derivatives net of tax	2,800,000
Derivative Liability, Fair Value	2,000,000
Prime Swaps [Member]
Interest Rate Derivatives Outstanding [Line Items]
Derivative Liability, Fair Value	2,300,000
Prime Rate [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives Outstanding [Line Items]
Notional amount of derivative contract	30,000,000
Interest rate swap fixed percentage	4.70%
Debt instrument description of variable rate basis	Prime
Debt instrument basis spread on variable rate	1.00%
Prime plus 1% [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives Outstanding [Line Items]
Notional amount of derivative contract	40,000,000
Interest rate swap fixed percentage	5.70%
Debt instrument description of variable rate basis	Prime plus 1%
Debt instrument basis spread on variable rate	1.00%
Prime plus 1% floored at 5% [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives Outstanding [Line Items]
Notional amount of derivative contract	100,000,000
Interest rate swap fixed percentage	6.01%
Debt instrument description of variable rate basis	Prime plus 1% floored at 5%
Debt instrument basis spread on variable rate	1.00%
Debt instrument interest floored rate	5.00%
Prime plus 1% floored at 5.5% [Member] | Interest Rate Swap [Member]
Interest Rate Derivatives Outstanding [Line Items]
Notional amount of derivative contract	$ 80,000,000
Interest rate swap fixed percentage	6.26%
Debt instrument description of variable rate basis	Prime plus 1% floored at 5.5%
Debt instrument basis spread on variable rate	1.00%
Debt instrument interest floored rate	5.50%