OTHER DEFERRED CREDITS AND OTHER LIABILITIES (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Deferred credits and other liabilities
Transmission easements	$ 20,235	$ 20,549
Operating lease liabilities - noncurrent	1,921	1,846
Contract liabilities (unearned revenue) - noncurrent	4,123	4,217
Customer deposits	2,251	3,015
Financial liabilities - reclamation	12,070	12,091
Other	13,795	14,681
Total other deferred credits and other liabilities	54,395	56,399
Transmission Right of Way Easements
Deferred credits and other liabilities
Total due for easement right of way	31,200
Other Deferred Credits and Other Liabilities | Transmission Right of Way Easements
Deferred credits and other liabilities
Transmission easements	$ 20,200	$ 20,500