Contractual interest rate for funds borrowed, under the debt agreement.

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The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Stated value of preferred units of ownership issued by a limited liability company (LLC).

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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The amount for notes payable (written promise to pay), payable to related parties, which are due after one year (or one business cycle).

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Change in the different classes of partners' capital accounts during the year due to acquisitions. Partners include general, limited and preferred partners.

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Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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RELATED PARTY TRANSACTIONS - Additional Information (Detail) - USD ($)			9 Months Ended	12 Months Ended
	Mar. 19, 2021	Jul. 01, 2020	Sep. 30, 2021	Dec. 31, 2020	Dec. 31, 2019	Oct. 02, 2019
Related Party Transaction [Line Items]
Related party loan outstanding balance			$ 0	$ 3,573,000	$ 12,700,000
Notes Payable Interest Rate At 8 With Due June 2021 [Member]
Related Party Transaction [Line Items]
Related party loan outstanding balance			0	2,382,000	0
Notes Payable Interest Rate At 8 With Due May 2021 [Member]
Related Party Transaction [Line Items]
Related party loan outstanding balance			0	1,191,000	0
Greenidge Blocker Corp [Member]
Related Party Transaction [Line Items]
Preferred unit, issued						15,000
Preferred unit, issuance value		$ 16,300,000				$ 15,000,000
Letter of Credit [Member]
Related Party Transaction [Line Items]
Net proceeds from new line of credit	$ 10,000
Line of credit			5,000.0	4,938,000	4,938,000
Letter of Credit [Member] \| Empire Pipeline Incorporated [Member]
Related Party Transaction [Line Items]
Repayments of lines of credit			3,600
Line of credit				3,630,000	3,630,000
Atlas [Member]
Related Party Transaction [Line Items]
Partners capital account, Acquisitions		$ 16,277,000
Limited guaranty payment			1,000,000.0
Exposure under guarantee			0
Atlas [Member] \| Letter of Credit [Member]
Related Party Transaction [Line Items]
Repayments of lines of credit				184,000	$ 206,000
Promissory Note Agreement [Member]
Related Party Transaction [Line Items]
Interest expense			$ 500,000	$ 20,000
Promissory Note Agreement [Member] \| Atlas [Member]
Related Party Transaction [Line Items]
Debt instrument, interest rate, stated percentage			8.00%	8.00%	8.00%
Interest expense				$ 553,000	$ 673,000
Promissory Note Agreement [Member] \| Atlas [Member] \| Notes Payable Interest Rate At 8 With Due June 2021 [Member]
Related Party Transaction [Line Items]
Maturity date				June 2021
Related party loan outstanding balance				$ 2,400
Promissory Note Agreement [Member] \| Atlas [Member] \| Notes Payable Interest Rate At 8 With Due May 2021 [Member]
Related Party Transaction [Line Items]
Maturity date				May 2021
Related party loan outstanding balance				$ 1,200