COMMITMENTS AND CONTINGENT LIABILITIES - Schedule of Commitment Expiration (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Guarantor Obligations [Line Items]
Total Amounts Committed	$ 717,010
Less Than 1 Year	623,240
1-3 Years	86,464
3-5 Years	6,576
Beyond 5 Years	730
Letters of Credit
Guarantor Obligations [Line Items]
Total Amounts Committed	115,774
Less Than 1 Year	113,274
1-3 Years	2,500
3-5 Years	0
Beyond 5 Years	0
Letters of Credit | Employee-Related
Guarantor Obligations [Line Items]
Total Amounts Committed	82,266
Less Than 1 Year	79,766
1-3 Years	2,500
3-5 Years	0
Beyond 5 Years	0
Letters of Credit | Environmental
Guarantor Obligations [Line Items]
Total Amounts Committed	398
Less Than 1 Year	398
1-3 Years	0
3-5 Years	0
Beyond 5 Years	0
Letters of Credit | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	33,110
Less Than 1 Year	33,110
1-3 Years	0
3-5 Years	0
Beyond 5 Years	0
Surety Bonds
Guarantor Obligations [Line Items]
Total Amounts Committed	570,034
Less Than 1 Year	501,005
1-3 Years	69,028
3-5 Years	1
Beyond 5 Years	0
Surety Bonds | Employee-Related
Guarantor Obligations [Line Items]
Total Amounts Committed	108,948
Less Than 1 Year	76,068
1-3 Years	32,880
3-5 Years	0
Beyond 5 Years	0
Surety Bonds | Environmental
Guarantor Obligations [Line Items]
Total Amounts Committed	456,350
Less Than 1 Year	420,439
1-3 Years	35,911
3-5 Years	0
Beyond 5 Years	0
Surety Bonds | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	4,736
Less Than 1 Year	4,498
1-3 Years	237
3-5 Years	1
Beyond 5 Years	0
Guarantees
Guarantor Obligations [Line Items]
Total Amounts Committed	31,202
Less Than 1 Year	8,961
1-3 Years	14,936
3-5 Years	6,575
Beyond 5 Years	730
Guarantees | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	31,202
Less Than 1 Year	8,961
1-3 Years	14,936
3-5 Years	6,575
Beyond 5 Years	$ 730