The amount by which the credit facility can be increased.

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Credit and loan agreement.

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The increase in basis points to the base interest rate in the event of a default on the credit agreement.

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Line of credit facility agreement maturity date.

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Line of credit facility extended maturity date.

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Line of credit facility optional extended maturity date.

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The length of time the Revolving Facility may be extended.

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The stated amount of the senior unsecured credit agreement which does not include the amount by which the credit facility can be increased.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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Face (par) amount of debt instrument at time of issuance.

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

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Date the debt instrument was issued, in CCYY-MM-DD format.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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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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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

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Date the credit facility first became available, in CCYY-MM-DD format.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

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No definition available.

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Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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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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Debt - Additional Information (Detail) - USD ($)			6 Months Ended		12 Months Ended
Debt - Additional Information (Detail) - USD ($)	Mar. 23, 2018	Jun. 02, 2015	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 14, 2020	Sep. 12, 2019
Credit and Loan Agreement [Line Items]
Credit agreement initiation date		Jun. 02, 2015
Senior unsecured revolving credit agreement		$ 225,000,000
Term loan under credit agreement		50,000,000
Borrowings under credit agreement			$ 17,500,000		$ 25,000,000
Repayment of borrowings under credit agreement, outstanding amount			$ 37,500,000	$ 10,000,000
Series A Note [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Feb. 25, 2021
Fifth Amended and Restated Prudential Agreement [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note, issuance date			Dec. 04, 2020
Amount of rate increase in case of default			2.00%
Fifth Amended and Restated Prudential Agreement [Member] \| Series A Note [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Feb. 25, 2021
Interest rate on agreement			6.00%
Senior unsecured note, aggregate amount issued			$ 100,000,000
Loss on extinguishment of debt			$ 1,233,000
Fifth Amended and Restated Prudential Agreement [Member] \| Series B Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Jun. 02, 2023
Interest rate on agreement			5.35%
Senior unsecured note, aggregate amount issued			$ 75,000,000
Fifth Amended and Restated Prudential Agreement [Member] \| Series C Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Feb. 25, 2025
Interest rate on agreement			4.75%
Senior unsecured note, aggregate amount issued			$ 50,000,000
Fifth Amended and Restated Prudential Agreement [Member] \| Series D Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Jun. 21, 2028
Interest rate on agreement			5.47%
Senior unsecured note, aggregate amount issued			$ 50,000,000
Fifth Amended and Restated Prudential Agreement [Member] \| Series F Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Sep. 12, 2029
Interest rate on agreement			3.52%
Senior unsecured note, aggregate amount issued			$ 50,000,000
Fifth Amended and Restated Prudential Agreement [Member] \| Series I Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Nov. 25, 2030
Interest rate on agreement			3.43%
Senior unsecured note, aggregate amount issued			$ 100,000,000
Fourth Restated Prudential Note Purchase Agreement [Member] \| Series E Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Jun. 21, 2018
Interest rate on agreement			5.47%
Senior unsecured note, aggregate amount issued			$ 50,000,000
First Amended and Restated AIG Agreement [Member] \| Series G Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Sep. 12, 2029
Interest rate on agreement			3.52%
Senior unsecured note, aggregate amount issued			$ 50,000,000
First Amended and Restated AIG Agreement [Member] \| Series J Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Nov. 25, 2030
Interest rate on agreement			3.43%
Senior unsecured note, aggregate amount issued			$ 50,000,000
First Amended and Restated MassMutual Agreement [Member] \| Series H Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Sep. 12, 2029
Interest rate on agreement			3.52%
Senior unsecured note, aggregate amount issued			$ 25,000,000
First Amended and Restated MassMutual Agreement [Member] \| Series K Notes [Member]
Credit and Loan Agreement [Line Items]
Senior unsecured note purchase agreement, maturity date			Nov. 25, 2030
Interest rate on agreement			3.43%
Senior unsecured note, aggregate amount issued			$ 25,000,000
Revolving Facility [Member]
Credit and Loan Agreement [Line Items]
Revolving facility under credit agreement	$ 175,000,000	$ 175,000,000					$ 250,000,000
Credit facility amount	$ 250,000,000						300,000,000
Credit agreement maturity date	Jun. 30, 2018
Credit agreement extended maturity date	Mar. 31, 2022
Credit facility agreement, optional extended maturity date			Mar. 31, 2023
Revolving facility optional extension period			1 year
Borrowings under credit agreement			$ 17,500,000		$ 25,000,000	$ 75,000,000
Senior unsecured note purchase agreement, maturity date			Mar. 31, 2022		Mar. 31, 2022
Interest rate on agreement			1.58%		1.58%
Repayment of borrowings under credit agreement, outstanding amount			$ 75,000,000
Revolving Facility [Member] \| Maximum [Member]
Credit and Loan Agreement [Line Items]
Option to increase credit facility			$ 300,000,000
Annual commitment fee on undrawn funds			0.25%
Revolving Facility [Member] \| Maximum [Member] \| Base Rate [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			1.30%
Revolving Facility [Member] \| Maximum [Member] \| LIBOR [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			2.30%
Revolving Facility [Member] \| Minimum [Member]
Credit and Loan Agreement [Line Items]
Annual commitment fee on undrawn funds			0.15%
Revolving Facility [Member] \| Minimum [Member] \| Base Rate [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			0.50%
Revolving Facility [Member] \| Minimum [Member] \| LIBOR [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			1.50%
Term Loan [Member]
Credit and Loan Agreement [Line Items]
Credit facility amount			$ 600,000,000				$ 0
Credit agreement maturity date	Jun. 30, 2020
Credit agreement extended maturity date	Mar. 31, 2023
Term Loan [Member] \| Maximum [Member] \| Base Rate [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			1.25%
Term Loan [Member] \| Maximum [Member] \| LIBOR [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			2.25%
Term Loan [Member] \| Minimum [Member] \| Base Rate [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			0.45%
Term Loan [Member] \| Minimum [Member] \| LIBOR [Member]
Credit and Loan Agreement [Line Items]
Credit agreement margin on borrowing base rate			1.45%