Fair Value Measurement - Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy (Detail) - Fair Value, Measurements, Nonrecurring - USD ($)		Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on a nonrecurring basis		$ 0	$ 0
ASSETS
Loans held for sale	[1]		0
Impaired loans	[1]	16,562,000	9,373,000
Other real estate owned	[1]	248,000	158,000
Mortgage servicing rights	[1]	3,112,000	3,396,000
Total Assets	[1]	19,922,000	12,927,000
Level 1
ASSETS
Loans held for sale	[1]	0	0
Impaired loans	[1]	0	0
Other real estate owned	[1]	0	0
Mortgage servicing rights	[1]	0	0
Total Assets	[1]	0	0
Level 2
ASSETS
Loans held for sale	[1]	0	0
Impaired loans	[1]	0	0
Other real estate owned	[1]	0	0
Mortgage servicing rights	[1]	0	0
Total Assets	[1]	0	0
Level 3
ASSETS
Loans held for sale	[1]	0	0
Impaired loans	[1]	16,562,000	9,373,000
Other real estate owned	[1]	248,000	158,000
Mortgage servicing rights	[1]	3,112,000	3,396,000
Total Assets	[1]	$ 19,922,000	$ 12,927,000

[1] This table represents only the nonrecurring items that are recorded at fair value in our financial statements.