SEGMENT REPORTING (Geographical Information) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 1,588,151
Property, plant and equipment, net		$ 1,561,978
Percent of property, plant and equipment, net	100.00%	100.00%
Permits and other intangibles, net	$ 419,066	$ 441,875
Percent of permits and other intangibles, net	100.00%	100.00%
Assets	$ 4,108,904	$ 3,738,321
United States
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 1,273,205
Property, plant and equipment, net		$ 1,233,949
Percent of property, plant and equipment, net	80.20%	79.00%
Permits and other intangibles, net	$ 372,609	$ 393,045
Percent of permits and other intangibles, net	88.90%	88.90%
Assets	$ 3,413,254	$ 3,090,311
Canada
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 314,946
Property, plant and equipment, net		$ 328,029
Percent of property, plant and equipment, net	19.80%	21.00%
Permits and other intangibles, net	$ 46,457	$ 48,830
Percent of permits and other intangibles, net	11.10%	11.10%
Assets	$ 695,650	$ 648,010