SEGMENT INFORMATION - Depreciation/Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Depreciation/amortization	$ 45,862	$ 44,666	$ 44,379
Amortization expense related to deferred financing cost	282	680	474
Unallocated
Segment Reporting Information [Line Items]
Depreciation/amortization	551	0	0
HNH | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	30,558	33,594	33,384
ANH | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	6,552	5,606	5,618
Specialty Products | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	7,401	4,092	4,097
Industrial Products | Operating Segments
Segment Reporting Information [Line Items]
Depreciation/amortization	$ 518	$ 694	$ 806