EMPLOYEE RETIREMENT PLANS - Qualified Defined-benefit Pension Plan Weighted Average Asset Allocation (Details) - Qualified	Dec. 31, 2016	Dec. 31, 2015
Plan Assets
Weighted average asset allocation (as a percent)	100.00%	100.00%
Equity securities
Plan Assets
Weighted average asset allocation (as a percent)	49.00%	49.00%
Debt securities
Plan Assets
Weighted average asset allocation (as a percent)	32.00%	32.00%
Other
Plan Assets
Weighted average asset allocation (as a percent)	19.00%	19.00%

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2446-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant