Fair Value - Quantitative Information about Significant Unobservable Inputs Used in Fair Value Measurements (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	13.00%	11.00%
Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 6,771	$ 13,332
Valuation Techniques	Fair value of collateral
Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 11,632	$ 11,857
Valuation Techniques	Fair value of collateral
Minimum [Member] | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	0.00%	0.00%
Minimum [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	10.00%	0.00%
Maximum [Member] | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	99.00%	86.00%
Maximum [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	67.00%	61.00%
Weighted Average [Member] | Commercial Loan [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	53.00%	28.00%
Weighted Average [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	36.00%	33.00%
Pooled Trust Preferred Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 8,119	$ 7,900
Valuation Techniques	Discounted cash flow
Pooled Trust Preferred Securities [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Additional asset defaults	4.50%	4.10%
Expected asset recoveries	0.00%	0.00%
Pooled Trust Preferred Securities [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Additional asset defaults	10.00%	11.50%
Expected asset recoveries	6.10%	11.50%
Pooled Trust Preferred Securities [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Additional asset defaults	7.90%	8.10%
Expected asset recoveries	0.90%	3.10%
Commercial Real Estate Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,352	$ 2,526
Valuation Techniques	Fair value of collateral
Commercial Real Estate Foreclosed Assets [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	4.00%	3.00%
Commercial Real Estate Foreclosed Assets [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	80.00%	80.00%
Commercial Real Estate Foreclosed Assets [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	39.00%	26.00%
Residential Foreclosed Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 394	$ 203
Valuation Techniques	Fair value of collateral
Residential Foreclosed Assets [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	7.00%	7.00%
Residential Foreclosed Assets [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	60.00%	53.00%
Residential Foreclosed Assets [Member] | Weighted Average [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Discount for type of property, age of appraisal and current status	30.00%	29.00%