SEGMENT INFORMATION - Schedule of Total Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Items excluded from segment assets:
Deferred tax assets	$ 67,538	$ 75,065
Segment Assets	2,729,116	$ 2,707,099	$ 2,685,076
Corporate Reconciling Items and Eliminations
Items excluded from segment assets:
Cash and other investments	190,777		72
Deferred tax assets	67,538		190,668
Reportable Segments | Operating Segments
Items excluded from segment assets:
Segment Assets	1,965,979		1,955,172
All Other Segments | Operating Segments
Items excluded from segment assets:
Segment Assets	$ 504,822		$ 539,164