STOCKHOLDERS'/OWNERS' EQUITY (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
Sep. 03, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Issuance of stock
Issuance of common stock (in shares)		2,276	718	656
Gross proceeds from issuance of common stock		$ 75,532	$ 22,120	$ 19,651
Equity Shelf Usd 500 Million 2015 Program [Member]
Issuance of stock
Sales price, equity distribution agreement	$ 500,000
Compensation percentage for sale of shares	2.00%
Issuance of common stock (in shares)		2,276	718	656
Issuance of common stock, average price per share		$ 33.18	$ 30.81	$ 29.97
Gross proceeds from issuance of common stock		$ 75,532	$ 22,120	$ 19,651

Number of new stock issued during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration