SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Accounting Standards (Details) $ in Millions	9 Months Ended
Sep. 30, 2017 USD ($)
Accounting Policies [Abstract]
Available for sale securities subject to new accounting guidance	$ 51.0
Available-for-sale securities, gross unrealized gain	$ 1.7

Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

Name:	us-gaap_AvailableForSaleSecuritiesGrossUnrealizedGains
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration