COMMITMENTS AND CONTINGENT LIABILITIES (Details) $ in Thousands	Sep. 30, 2017 USD ($)
Guarantor Obligations [Line Items]
Total Amounts Committed	$ 724,583
Less Than 1 Year	639,741
1-3 Years	74,137
3-5 Years	9,876
Beyond 5 Years	829
Letters of Credit
Guarantor Obligations [Line Items]
Total Amounts Committed	94,680
Less Than 1 Year	48,416
1-3 Years	46,264
3-5 Years	0
Beyond 5 Years	0
Letters of Credit | Employee-Related
Guarantor Obligations [Line Items]
Total Amounts Committed	83,836
Less Than 1 Year	46,214
1-3 Years	37,622
3-5 Years	0
Beyond 5 Years	0
Letters of Credit | Environmental
Guarantor Obligations [Line Items]
Total Amounts Committed	998
Less Than 1 Year	998
1-3 Years	0
3-5 Years	0
Beyond 5 Years	0
Letters of Credit | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	9,846
Less Than 1 Year	1,204
1-3 Years	8,642
3-5 Years	0
Beyond 5 Years	0
Surety Bonds
Guarantor Obligations [Line Items]
Total Amounts Committed	593,589
Less Than 1 Year	581,573
1-3 Years	12,015
3-5 Years	1
Beyond 5 Years	0
Surety Bonds | Employee-Related
Guarantor Obligations [Line Items]
Total Amounts Committed	109,660
Less Than 1 Year	106,980
1-3 Years	2,680
3-5 Years	0
Beyond 5 Years	0
Surety Bonds | Environmental
Guarantor Obligations [Line Items]
Total Amounts Committed	477,152
Less Than 1 Year	467,991
1-3 Years	9,161
3-5 Years	0
Beyond 5 Years	0
Surety Bonds | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	6,777
Less Than 1 Year	6,602
1-3 Years	174
3-5 Years	1
Beyond 5 Years	0
Guarantees
Guarantor Obligations [Line Items]
Total Amounts Committed	36,314
Less Than 1 Year	9,752
1-3 Years	15,858
3-5 Years	9,875
Beyond 5 Years	829
Guarantees | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	36,314
Less Than 1 Year	9,752
1-3 Years	15,858
3-5 Years	9,875
Beyond 5 Years	$ 829