Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
ASSETS MEASURED ON A NONRECURRING BASIS
Loans held for sale	$ 0	$ 0
Nonrecurring [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Impaired loans		5,000,000
Loans held for sale	0	0
Accrued income and other assets	7,000,000	7,000,000
Total assets at fair value	7,000,000	12,000,000
Nonrecurring [Member] | Level 1 [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Loans held for sale	0	0
Nonrecurring [Member] | Level 2 [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Loans held for sale	0	0
Nonrecurring [Member] | Level 3 [Member]
ASSETS MEASURED ON A NONRECURRING BASIS
Impaired loans		5,000,000
Loans held for sale	0	0
Accrued income and other assets	7,000,000	7,000,000
Total assets at fair value	$ 7,000,000	$ 12,000,000