COMMITMENTS AND CONTINGENT LIABILITIES - Schedule of Commitment Expiration (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Guarantor Obligations [Line Items]
Total Amounts Committed	$ 767,176
Less Than 1 Year	667,557
1-3 Years	98,690
3-5 Years	398
Beyond 5 Years	531
Letters of Credit
Guarantor Obligations [Line Items]
Total Amounts Committed	98,479
Less Than 1 Year	81,627
1-3 Years	16,852
3-5 Years	0
Beyond 5 Years	0
Letters of Credit | Employee-Related
Guarantor Obligations [Line Items]
Total Amounts Committed	68,583
Less Than 1 Year	51,731
1-3 Years	16,852
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	29,498
Less Than 1 Year	29,498
1-3 Years	0
3-5 Years	0
Beyond 5 Years	0
Surety Bonds
Guarantor Obligations [Line Items]
Total Amounts Committed	646,456
Less Than 1 Year	577,824
1-3 Years	68,632
3-5 Years	0
Beyond 5 Years	0
Surety Bonds | Employee-Related
Guarantor Obligations [Line Items]
Total Amounts Committed	104,033
Less Than 1 Year	72,351
1-3 Years	31,682
3-5 Years	0
Beyond 5 Years	0
Surety Bonds | Environmental
Guarantor Obligations [Line Items]
Total Amounts Committed	538,698
Less Than 1 Year	502,039
1-3 Years	36,659
3-5 Years	0
Beyond 5 Years	0
Surety Bonds | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	3,725
Less Than 1 Year	3,434
1-3 Years	291
3-5 Years	0
Beyond 5 Years	0
Guarantees
Guarantor Obligations [Line Items]
Total Amounts Committed	22,241
Less Than 1 Year	8,106
1-3 Years	13,206
3-5 Years	398
Beyond 5 Years	531
Guarantees | Other
Guarantor Obligations [Line Items]
Total Amounts Committed	22,241
Less Than 1 Year	8,106
1-3 Years	13,206
3-5 Years	398
Beyond 5 Years	$ 531