LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Non Traditional Mortgage Performance by Credit Score (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) Loan	Dec. 31, 2016 USD ($) Loan
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	$ 6,659,407	$ 6,034,752
NTM Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	$ 806,933	$ 885,148
Consumer \| NTM Loans
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	592	663
Total loans and leases	$ 806,933	$ 885,148
Increase (decrease) in loans receivable	$ (78,200)
Increase (decrease) in loans receivable, percentage	(8.80%)
Consumer \| NTM Loans \| First lien
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	580	651
Total loans and leases	$ 803,355	$ 881,589
Consumer \| NTM Loans \| Green Loans
Financing Receivable, Recorded Investment [Line Items]
Total loans and leases	$ 85,800	$ 91,000
Consumer \| NTM Loans \| Green Loans \| First lien
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	101	107
Total loans and leases	$ 82,197	$ 87,469
Count Change \| Loan	0
Increase (decrease) in loans receivable	$ 0
Increase (decrease) in loans receivable, percentage	0.00%
Consumer \| NTM Loans \| Green Loans \| First lien \| Loan Portfolio Concentration Risk \| Non-Traditional Single Family Residential Mortgage Green Loans First Lien Portfolio
Financing Receivable, Recorded Investment [Line Items]
Percentage to total loans and leases	100.00%
Consumer \| NTM Loans \| Green Loans \| First lien \| Greater than 800
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	12	15
Total loans and leases	$ 7,737	$ 9,091
Count Change \| Loan	(3)
Increase (decrease) in loans receivable	$ (1,354)
Increase (decrease) in loans receivable, percentage	(1.70%)
Consumer \| NTM Loans \| Green Loans \| First lien \| Greater than 800 \| Loan Portfolio Concentration Risk \| Non-Traditional Single Family Residential Mortgage Green Loans First Lien Portfolio
Financing Receivable, Recorded Investment [Line Items]
Percentage to total loans and leases	9.40%	11.10%
Consumer \| NTM Loans \| Green Loans \| First lien \| 700-799
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	57	50
Total loans and leases	$ 42,397	$ 38,486
Count Change \| Loan	7
Increase (decrease) in loans receivable	$ 3,911
Increase (decrease) in loans receivable, percentage	4.80%
Consumer \| NTM Loans \| Green Loans \| First lien \| 700-799 \| Loan Portfolio Concentration Risk \| Non-Traditional Single Family Residential Mortgage Green Loans First Lien Portfolio
Financing Receivable, Recorded Investment [Line Items]
Percentage to total loans and leases	51.60%	46.80%
Consumer \| NTM Loans \| Green Loans \| First lien \| 600-699
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	23	28
Total loans and leases	$ 23,467	$ 27,420
Count Change \| Loan	(5)
Increase (decrease) in loans receivable	$ (3,953)
Increase (decrease) in loans receivable, percentage	(4.80%)
Consumer \| NTM Loans \| Green Loans \| First lien \| 600-699 \| Loan Portfolio Concentration Risk \| Non-Traditional Single Family Residential Mortgage Green Loans First Lien Portfolio
Financing Receivable, Recorded Investment [Line Items]
Percentage to total loans and leases	28.50%	33.30%
Consumer \| NTM Loans \| Green Loans \| First lien \| Less than 600
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	5	1
Total loans and leases	$ 4,691	$ 1,800
Count Change \| Loan	4
Increase (decrease) in loans receivable	$ 2,891
Increase (decrease) in loans receivable, percentage	3.50%
Consumer \| NTM Loans \| Green Loans \| First lien \| Less than 600 \| Loan Portfolio Concentration Risk \| Non-Traditional Single Family Residential Mortgage Green Loans First Lien Portfolio
Financing Receivable, Recorded Investment [Line Items]
Percentage to total loans and leases	5.70%	2.20%
Consumer \| NTM Loans \| Green Loans \| First lien \| No FICO
Financing Receivable, Recorded Investment [Line Items]
Count \| Loan	4	7
Total loans and leases	$ 3,905	$ 5,400
Count Change \| Loan	(3)
Increase (decrease) in loans receivable	$ (1,495)
Increase (decrease) in loans receivable, percentage	(1.80%)
Consumer \| NTM Loans \| Green Loans \| First lien \| No FICO \| Loan Portfolio Concentration Risk \| Non-Traditional Single Family Residential Mortgage Green Loans First Lien Portfolio
Financing Receivable, Recorded Investment [Line Items]
Percentage to total loans and leases	4.80%	6.60%

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Loans and Leases Receivable, Net Of Deferred Income, Increase (Decrease) in Period

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Loans and Leases Receivable, Net Of Deferred Income, Percentage Increase (Decrease) in Period

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Indicates the number of mortgages under each classification.

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