FAIR VALUES OF FINANCIAL INSTRUMENTS - Carrying Amounts and Estimated Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financial assets
Cash and cash equivalents	$ 313,850	$ 391,592
Securities available-for-sale	1,167,687	1,992,500
Federal Home Loan Bank and other bank stock	76,373	68,094
Loans held-for-sale, carried at fair value	23,794	27,606
Loans held-for-sale, carried at lower of cost or fair value	573,926	426
Loans receivable, net of ALLL	6,550,673	7,513,910
Accrued interest receivable	31,908	38,807
Derivative assets	4,149	1,534
Financial liabilities
Deposits	6,231,819	7,689,324
Advances from Federal Home Loan Bank	1,850,016	1,517,761
Long term debt	177,693	174,059
Derivative liabilities	14,055	1,600
Accrued interest payable	9,681	13,253
Recurring \| Discontinued Operations, Disposed of by Sale \| Banc Home Loan
Financial liabilities
Loans held-for-sale, carried at fair value		19,500
Nonrecurring \| Discontinued Operations, Disposed of by Sale \| Banc Home Loan
Financial liabilities
Loans held-for-sale, carried at fair value		19,500
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial assets
Cash and cash equivalents	313,850	391,592
Securities available-for-sale	0	0
Federal Home Loan Bank and other bank stock	0	0
Loans held-for-sale, carried at fair value	0	0
Loans held-for-sale, carried at lower of cost or fair value	0
Loans receivable, net of ALLL	0	0
Accrued interest receivable	31,908	38,807
Derivative assets	0	0
Financial liabilities
Deposits	0	0
Advances from Federal Home Loan Bank	0	0
Long term debt	0	0
Derivative liabilities	0	0
Accrued interest payable	9,681	13,253
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Recurring
Financial assets
Loans held-for-sale, carried at fair value	0	0
Significant Other Observable Inputs (Level 2)
Financial assets
Cash and cash equivalents	0	0
Securities available-for-sale	1,167,687	1,992,500
Federal Home Loan Bank and other bank stock	76,373	68,094
Loans held-for-sale, carried at fair value	2,719	2,566
Loans held-for-sale, carried at lower of cost or fair value	0
Loans receivable, net of ALLL	0	0
Accrued interest receivable	0	0
Derivative assets	4,149	1,534
Financial liabilities
Deposits	0	0
Advances from Federal Home Loan Bank	1,850,016	1,517,761
Long term debt	177,693	174,059
Derivative liabilities	14,055	1,600
Accrued interest payable	0	0
Significant Other Observable Inputs (Level 2) \| Recurring
Financial assets
Loans held-for-sale, carried at fair value	2,719	2,140
Significant Other Observable Inputs (Level 2) \| Recurring \| Discontinued Operations, Disposed of by Sale \| Banc Home Loan
Financial liabilities
Loans held-for-sale, carried at fair value		2,100
Significant Other Observable Inputs (Level 2) \| Nonrecurring \| Discontinued Operations, Disposed of by Sale \| Banc Home Loan
Financial liabilities
Loans held-for-sale, carried at fair value		2,100
Significant Unobservable Inputs (Level 3)
Financial assets
Cash and cash equivalents	0	0
Securities available-for-sale	0	0
Federal Home Loan Bank and other bank stock	0	0
Loans held-for-sale, carried at fair value	21,075	25,040
Loans held-for-sale, carried at lower of cost or fair value	578,911
Loans receivable, net of ALLL	6,550,673	7,513,910
Accrued interest receivable	0	0
Derivative assets	0	0
Financial liabilities
Deposits	6,231,819	7,689,324
Advances from Federal Home Loan Bank	0	0
Long term debt	0	0
Derivative liabilities	0	0
Accrued interest payable	0	0
Significant Unobservable Inputs (Level 3) \| Recurring
Financial assets
Loans held-for-sale, carried at fair value	21,075	25,040
Significant Unobservable Inputs (Level 3) \| Recurring \| Discontinued Operations, Disposed of by Sale \| Banc Home Loan
Financial liabilities
Loans held-for-sale, carried at fair value		17,400
Significant Unobservable Inputs (Level 3) \| Nonrecurring \| Discontinued Operations, Disposed of by Sale \| Banc Home Loan
Financial liabilities
Loans held-for-sale, carried at fair value		17,400
Carrying Value
Financial assets
Cash and cash equivalents	313,850	391,592
Securities available-for-sale	1,167,687	1,992,500
Federal Home Loan Bank and other bank stock	76,373	68,094
Loans held-for-sale, carried at fair value	23,794	27,606
Loans held-for-sale, carried at lower of cost or fair value	573,926
Loans receivable, net of ALLL	6,660,047	7,638,681
Accrued interest receivable	31,908	38,807
Derivative assets	4,149	1,534
Financial liabilities
Deposits	6,292,290	7,916,644
Advances from Federal Home Loan Bank	1,825,000	1,520,000
Long term debt	173,257	173,174
Derivative liabilities	14,055	1,600
Accrued interest payable	9,681	13,253
Carrying Value \| Recurring
Financial assets
Loans held-for-sale, carried at fair value	$ 23,794	$ 27,180

Disposal Group, Including Discontinued Operation, Loans Receivable Held-For-Sale, Net

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Investment in Federal Home Loan and Other Banks Stock, Fair Value Disclosure

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The aggregate amount of loans receivable that will be sold to other entities. Includes mortgage and all other loans (collectively, loans) not classified as held for investment. Such loans are stated at the lower of cost or market (approximates fair value) or fair value if the fair value option under SFAS 159 has been elected. Mortgage loans exclude mortgage-backed securities which are considered a debt security (other loan).

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Loans Held-for-sale, Fair Value Disclosure and Disposal Group, Including Discontinued Operation, Loans Held-for-sale, Fair Value Disclosure

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Fair value portion of amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties.

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Fair value portion of accrued expenses.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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