FAIR VALUE - Impairment of Valuation Adjustments were Recorded for Assets Recognized at Fair Value (Detail) - Fair Value Measurements Nonrecurring [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Fair Value Inputs Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans receivable	$ 0	[1]	$ 0	[2]	$ 0	[3]
Other Real Estate Owned	0	[4]	0	[5]	0	[6]
Mortgage servicing rights			0	[7]	0	[8]
Loans held for sale	0
Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans receivable	0	[1]	0	[2]	0	[3]
Other Real Estate Owned	0	[4]	0	[5]	0	[6]
Mortgage servicing rights			0	[7]	0	[8]
Loans held for sale	0
Fair Value Inputs Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Loans receivable	365,726	[1]	410,428	[2]	442,081	[3]
Other Real Estate Owned	131,402	[4]	147,940	[5]	137,681	[6]
Mortgage servicing rights			25,255	[7]	26,244	[8]
Loans held for sale	16,111
Fair Value Inputs Level 3 [Member] | OREO [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets Fair Value Adjustment	(11,499)		(8,511)		(7,873)
Fair Value Inputs Level 3 [Member] | Mortgage Servicing Rights [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets Fair Value Adjustment			(1,611)		(325)
Fair Value Inputs Level 3 [Member] | Loans Held For Sale [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets Fair Value Adjustment	(10,102)
Fair Value Inputs Level 3 [Member] | Loans Receivable [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Assets Fair Value Adjustment	$ (29,799)		$ (39,493)	[2]	$ (49,884)	[3]

[1] Consists mainly of impaired commercial and construction loans. The impairments were generally measured based on the fair value of the collateral. The fair values were derived from external appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the collateral (e.g., absorption rates), which are not market observable.

[2] Consists mainly of impaired commercial and construction loans. The impairments were generally measured based on the fair value of the collateral. The fair values were derived from external appraisals that take into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the collateral (e.g., absorption rates), which are not market observable.

[3] Consists mainly of impaired commercial and construction loans. The impairments were generally measured based on the fair value of the collateral. The fair values were derived from external appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the collateral (e.g., absorption rates), which are not market observable.

[4] The fair values were derived from appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the properties (e.g., absorption rates and net operating income of income producing properties), which are not market observable. Losses were related to market valuation adjustments after the transfer of the loans to the OREO portfolio.

[5] The fair values were derived from appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the properties (e.g., absorption rates and net operating income of income producing properties), which are not market observable. Losses were related to market valuation adjustments after the transfer of the loans to the OREO portfolio.

[6] The fair values were derived from appraisals that took into consideration prices in observed transactions involving similar assets in similar locations but adjusted for specific characteristics and assumptions of the properties (e.g., absorption rates and net operating income of income producing properties), which are not market observable. Losses were related to market valuation adjustments after the transfer of the loans to the OREO portfolio.

[7] Fair value adjustments to mortgage servicing rights were mainly due to assumptions associated with mortgage prepayment rates. The Corporation carries its mortgage servicing rights at the lower of cost or market, measured at fair value on a non-recurring basis. Assumptions for the value of mortgage servicing rights include: Prepayment rate 6.30%, Discount rate 11.23%.

[8] Fair value adjustments to the mortgage servicing rights were mainly due to assumptions associated with mortgage prepayments rates. The Corporation carries its mortgage servicing rights at the lower of cost or market, measured at fair value on a non-recurring basis. Assumptions for the value of mortgage servicing rights include: Prepayment rate 6.12%, Discount rate 11.19%.