DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING - Schedule of derivative financial instruments (Details) - Designated as hedges - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Interest rate swaps
Derivative financial instruments and hedging
Notional Amount	$ 400,000	$ 400,000
Fair Value	$ (7,139)	(1,581)
Interest Rate Swap Expiring January 31, 2023
Derivative financial instruments and hedging
Derivative average fixed interest rate	1.98%
Interest Rate Swap Expiring January 31, 2023 One
Derivative financial instruments and hedging
Notional Amount	$ 100,000	100,000
Fair Value	630	1,758
Interest Rate Swap Expiring January 31, 2023 Two
Derivative financial instruments and hedging
Notional Amount	100,000	100,000
Fair Value	585	1,703
Interest Rate Swap Expiring September 30, 2024
Derivative financial instruments and hedging
Notional Amount	75,000	75,000
Fair Value	$ (2,731)	(1,656)
Derivative average fixed interest rate	2.87%
Interest Rate Swap Expiring December 31, 2025
Derivative financial instruments and hedging
Notional Amount	$ 125,000	125,000
Fair Value	$ (5,623)	$ (3,386)
Derivative average fixed interest rate	2.93%

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

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- Definition

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.

+ References

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