Fair Value Measurement - Quantitative Information about Level 3 Fair Value Measurements for Financial Instruments Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,318	$ 4,649
Foreclosed Assets [Member] | Land & Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		96
Foreclosed Assets [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,396	1,177
Foreclosed Assets [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value		$ 267
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales	0.00%	(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Foreclosed Assets [Member] | Land & Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales		(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Foreclosed Assets [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales	(5.00%)	(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Minimum [Member] | Foreclosed Assets [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales		(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales	(5.00%)	(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Foreclosed Assets [Member] | Land & Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales		(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Foreclosed Assets [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales	(5.00%)	(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Maximum [Member] | Foreclosed Assets [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales		(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales	(5.00%)	(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Foreclosed Assets [Member] | Land & Construction [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales		(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Foreclosed Assets [Member] | Residential Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales	(5.00%)	(5.00%)
Level 3 [Member] | Sales Comparison Approach [Member] | Weighted Average [Member] | Foreclosed Assets [Member] | Commercial Real Estate [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Adjustment for differences between comparable sales		(5.00%)
Level 3 [Member] | Income Approach [Member] | Minimum [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization rate		7.00%
Level 3 [Member] | Income Approach [Member] | Maximum [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization rate		8.00%
Level 3 [Member] | Income Approach [Member] | Weighted Average [Member] | Impaired Originated & PNCI Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization rate		7.25%