COMMITMENTS AND CONTINGENCIES (Superfund Proceedings) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 sites	Dec. 31, 2002 acre
Superfund Proceedings
Number of sites owned by the entity subject to proceedings under federal or state superfund laws	126
Superfund Proceedings
Superfund Proceedings
Number of sites subject to proceedings under federal or state superfund laws	126
Number of sites owned by the entity subject to proceedings under federal or state superfund laws	2
Number of sites owned by third parties subject to proceedings under federal or state Superfund laws	124
Third party sites requiring expenditure on remediation	22
Number of sites for which environmental remediation expense is settled	29
Number of sites for which environmental remediation expense is not required	73
Possible increase in legal and administrative proceedings	100
Number of sites which potential liability could exceed $100,000	13
Notices received from owners of third party sites seeking indemnification from the company	5
Wichita Property
Superfund Proceedings
State-designated superfund site acquired, total acres		1,400
Certain other third party sites
Superfund Proceedings
Indemnification agreement with third party sites	11
Safety-Kleen
Superfund Proceedings
Notices received from owners of third party sites seeking indemnification from the company	16