Fair Value Measurements - Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy (Detail) - Fair Value, Measurements, Nonrecurring - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Impaired loans	$ 9,373	$ 12,916
Other real estate owned	158	117
Mortgage servicing rights	3,396	2,934
Total Assets	12,927	15,967
Level 1
ASSETS
Impaired loans	0	0
Other real estate owned	0	0
Mortgage servicing rights	0	0
Level 2
ASSETS
Impaired loans	0	0
Other real estate owned	0	0
Mortgage servicing rights	0	0
Level 3
ASSETS
Impaired loans	9,373	12,916
Other real estate owned	158	117
Mortgage servicing rights	3,396	2,934
Total Assets	$ 12,927	$ 15,967