Debt - Additional Information (Detail) ¥ in Thousands, £ in Thousands		1 Months Ended	12 Months Ended
	Mar. 04, 2019 USD ($)	Sep. 30, 2018	Dec. 31, 2019 USD ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2018 CNY (¥)
Line Of Credit Facility [Line Items]
Future principal payments, next twelve months			$ 20,363,000
Future principal payments, in year two			34,209,000
Future principal payments, in year three			1,822,000
Future principal payments, in year four			1,802,000
Future principal payments, in year five			1,714,000
Future principal payments, thereafter			$ 10,947,000
Lessee lease term		20 years
Lessee, operating lease, option to extend		UES may extend the lease for four successive periods of approximately five years each. If fully extended, the lease would expire in September 2058.
Lessee, operating term period		5 years
Extended lease expiration date		2058-09
Lease repurchase percentage on lessor investment for properties		115.00%
Effective interest rate			8.21%				8.21%	8.21%
Repayment of promissory notes and related accrued interest	$ 26,474,000		$ 28,226,000		$ 1,213,000
Accrued interest			$ 2,225,000		2,333,000
Weighted average remaining lease term			3 years				3 years	3 years
Cash paid for finance lease liabilities			$ 203,000
Cash outflow from operating lease			22,000
Cash outflow from financing lease			181,000
Industrial Revenue Bonds ("IRB") [Member]
Line Of Credit Facility [Line Items]
Long term debt			13,311,000		13,311,000
Minority Shareholder Loan [Member]
Line Of Credit Facility [Line Items]
Long term debt			$ 2,856,000		4,056,000			¥ 19,901	¥ 27,901
Effective interest rate			5.00%				5.00%	5.00%
Accrued interest			$ 2,152,000		2,297,000			¥ 14,999	15,800
Repayment, principal amount			1,148,000	¥ 8,000	449,000	¥ 3,090
Repayment, interest amount			$ 287,000	¥ 2,000	145,000	¥ 1,000
Debt instrument conversion of loan to equity					1,308,000				9,000
Minority Shareholder Loan [Member] | TISCO [Member]
Line Of Credit Facility [Line Items]
Debt instrument conversion of loan to equity					872,000				¥ 6,000
Minimum [Member] | Capital Leases [Member]
Line Of Credit Facility [Line Items]
Effective interest rate			1.30%				1.30%	1.30%
Maximum [Member]
Line Of Credit Facility [Line Items]
Incremental Percentage On Annual Lease Payment		2.00%
Change In Consumer Price Index Percentage		1.25%
Maximum [Member] | Capital Leases [Member]
Line Of Credit Facility [Line Items]
Effective interest rate			3.20%				3.20%	3.20%
Revolving Credit and Security Agreement [Member]
Line Of Credit Facility [Line Items]
Initial term of credit facility			5 years	5 years
Agreement borrowing capacity			$ 100,000,000
Additional borrowing capacity			50,000,000
Long term debt			$ 34,273,000		$ 14,320,000
Interest on outstanding balance			4.00%	4.00%
Line of credit, remaining borrowing capacity			$ 27,000,000
Revolving Credit and Security Agreement [Member] | Minimum [Member]
Line Of Credit Facility [Line Items]
Commitment fee payable percentage			0.25%	0.25%
Revolving Credit and Security Agreement [Member] | Maximum [Member]
Line Of Credit Facility [Line Items]
Commitment fee payable percentage			0.375%	0.375%
Fixed charge coverage ratio			1.00				1.00	1.00
Revolving Credit and Security Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member]
Line Of Credit Facility [Line Items]
Debt instrument description of interest rate			LIBOR plus an applicable margin ranging between 1.75% to 2.25%	LIBOR plus an applicable margin ranging between 1.75% to 2.25%
Revolving Credit and Security Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Line Of Credit Facility [Line Items]
Debt instrument basis spread			1.75%	1.75%
Revolving Credit and Security Agreement [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Line Of Credit Facility [Line Items]
Debt instrument basis spread			2.25%	2.25%
Revolving Credit and Security Agreement [Member] | Base Rate [Member]
Line Of Credit Facility [Line Items]
Debt instrument description of interest rate			the base rate plus an applicable margin ranging between 0.75% to 1.25%	the base rate plus an applicable margin ranging between 0.75% to 1.25%
Revolving Credit and Security Agreement [Member] | Base Rate [Member] | Minimum [Member]
Line Of Credit Facility [Line Items]
Debt instrument basis spread			0.75%	0.75%
Revolving Credit and Security Agreement [Member] | Base Rate [Member] | Maximum [Member]
Line Of Credit Facility [Line Items]
Debt instrument basis spread			1.25%	1.25%
Revolving Credit and Security Agreement [Member] | Union Electric Steel UK Limited [Member]
Line Of Credit Facility [Line Items]
Long term debt | £							£ 2,000
Revolving Credit and Security Agreement [Member] | Letter of Credit [Member]
Line Of Credit Facility [Line Items]
Agreement borrowing capacity			$ 40,000,000
Revolving Credit and Security Agreement [Member] | European Credit Facility [Member]
Line Of Credit Facility [Line Items]
Agreement borrowing capacity			15,000,000
Revolving Credit and Security Agreement [Member] | Canadian Credit Facility [Member]
Line Of Credit Facility [Line Items]
Agreement borrowing capacity			15,000,000
Tax Exempt Industrial Revenue Bond One [Member] | Industrial Revenue Bonds ("IRB") [Member]
Line Of Credit Facility [Line Items]
Tax-exempt IRB maturing in 2020/2027/2029			$ 4,120,000
Interest at a floating rate on tax-exempt IRB maturing in 2020/2027/2029			1.50%				1.50%	1.50%
Taxable Industrial Revenue Bond [Member] | Industrial Revenue Bonds ("IRB") [Member]
Line Of Credit Facility [Line Items]
Tax-exempt IRB maturing in 2020/2027/2029			$ 7,116,000
Interest at a floating rate on tax-exempt IRB maturing in 2020/2027/2029			2.25%				2.25%	2.25%
Tax Exempt Industrial Revenue Bond Two [Member] | Industrial Revenue Bonds ("IRB") [Member]
Line Of Credit Facility [Line Items]
Tax-exempt IRB maturing in 2020/2027/2029			$ 2,075,000
Interest at a floating rate on tax-exempt IRB maturing in 2020/2027/2029			1.66%				1.66%	1.66%