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Stockholders' Equity - Narrative (Details) $ / shares in Units, $ in Thousands		1 Months Ended				6 Months Ended
	Aug. 10, 2021 $ / shares	Sep. 30, 2021 classOfStock $ / shares shares	Jun. 30, 2021 shares	Mar. 31, 2021 $ / shares shares	Jun. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) classOfStock $ / shares shares	Sep. 30, 2020 USD ($)
Equity [Abstract]
Number of classes of common stock outstanding | classOfStock		2				2
Preferred stock, shares authorized (in shares)		25,000,000				25,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.001				$ 0.001
Preferred stock, shares issued (in shares)		0				0
Preferred stock, shares outstanding (in shares)		0				0
Subsidiary, Sale of Stock [Line Items]
Purchase of non-controlling interests | $						$ 3,046	$ 131,294
Sale of partnership interests | $						$ 0	$ 3,308
Dividend (in dollars per share) | $ / shares	$ 0.07
SRA
Subsidiary, Sale of Stock [Line Items]
Purchase of non-controlling interests | $					$ 3,300
Sale of partnership interests | $					$ 3,300
Public offering
Subsidiary, Sale of Stock [Line Items]
Shares sold in offering (in shares)				9,200,000
Offering price per share (in dollars per share) | $ / shares				$ 29.50
Underwriters' option
Subsidiary, Sale of Stock [Line Items]
Shares sold in offering (in shares)				1,200,000
Class A Common Stock
Subsidiary, Sale of Stock [Line Items]
Share exchange, shares issued (in shares)		2,087,281	1,898,438	9,200,000
Class A Common Stock | Greenspring
Subsidiary, Sale of Stock [Line Items]
Stock issued for acquisition (in shares)		12,686,756
Class C units
Subsidiary, Sale of Stock [Line Items]
Conversion basis (in shares)						1
Class C units | Greenspring
Subsidiary, Sale of Stock [Line Items]
Stock issued for acquisition (in shares)		3,071,519
Class B Common Stock
Subsidiary, Sale of Stock [Line Items]
Share exchange, shares exchanged (in shares)		2,087,281	1,898,438	9,200,000
SRA
Subsidiary, Sale of Stock [Line Items]
Noncontrolling interest, ownership by parent		49.00%				49.00%
Noncontrolling interest, ownership by noncontrolling owners		51.00%				51.00%

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Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer.

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