SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Summary of Impact of Topic 606 Adoption on Unaudited Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Assets
Accounts receivable	$ 68,811
Property, plant and equipment, net	1,858,312	$ 1,828,252	$ 1,795,129
Liabilities
Deferred revenue	10,159	10,088	4,000
Deferred revenue, noncurrent	36,587	35,528	12,707
Partners' Capital	1,032,442	1,088,644
Balances Without Adoption of Topic 606
Assets
Accounts receivable	66,386
Property, plant and equipment, net	1,824,484		1,795,129
Liabilities
Deferred revenue	4,071		4,000
Deferred revenue, noncurrent	12,707		12,707
Partners' Capital	1,026,157		1,084,430
Effect of Change Increase / (Decrease)
Liabilities
Deferred revenue			6,088
Deferred revenue, noncurrent			$ 22,821
Accounting Standard Update 2014-09 | Effect of Change Increase / (Decrease)
Assets
Accounts receivable	2,425
Property, plant and equipment, net	33,828	33,123
Liabilities
Deferred revenue	6,088	6,088
Deferred revenue, noncurrent	23,880	22,821
Partners' Capital	$ 6,285	$ 4,214