Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Description of service or performance condition required to be met for earning right to award under share-based payment arrangement. Includes, but is not limited to, combination of market, performance or service condition.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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STOCK-BASED COMPENSATION - Performance Units - Additional Information (Detail) - Omnibus Plan [Member] - Performance Shares [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additions			160,485
Stock-based compensation expense	$ 0.5	$ 0.5	$ 1.5	$ 1.3
Unrecognized compensation cost related to unvested performance units	$ 2.9		$ 2.9
Vested			304,408
Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additions			160,485	502,307	200,053
Performance Units Program Description			The performance units will vest on the third anniversary of the effective date of the awards, subject to the achievement of a pre-established tangible book value per share target as of December 31, 2023. All the performance units will vest if performance is at the pre-established performance target level or above. However, the participants may vest with respect to 50% of the awards to the extent that performance is below the target but not less than 80% of the pre-established performance target level (the “80% minimum threshold”), which is measured based upon the growth in the tangible book value during the performance cycle. If performance is between the 80% minimum threshold and the pre-established performance target level, the participants will vest on a proportional amount. No performance units will vest if performance is below the 80% minimum threshold.
Vested			304,408