LEASES, Future Minimum Lease Payments Under Operating Leases (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
LEASES [Abstract]
Percentage of costs relate to service costs for leased towing vessels	75.00%
Future Minimum Lease Payments Under Operating Leases [Abstract]
2019	$ 9,503,000
2020	33,200,000
2021	25,550,000
2022	22,573,000
2023	18,684,000
Thereafter	95,939,000
Total lease payments	205,449,000
Less: imputed interest	(41,431,000)
Operating lease liabilities	$ 164,018,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019		$ 97,091,000
2020		30,062,000
2021		21,818,000
2022		20,263,000
2023		17,429,000
Thereafter		91,939,000
Future minimum lease payments under operating leases		$ 278,602,000