Investments in Debt Securities (Tables)  | 
6 Months Ended | ||||||||||||||||||||||||
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Dec. 31, 2020  | |||||||||||||||||||||||||
| Investments in Debt Securities | |||||||||||||||||||||||||
| Schedule of components of investments in debt securities | 
 The components of investments in debt securities are as follows (in thousands): 
 
 
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| Schedule of fair value of available-for-sale debt securities, by contractual maturity | 
 The fair value of available-for-sale debt securities, by contractual maturity, as of December 31, 2020, was as follows (in thousands): 
 
 
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