Recent accounting pronouncements (Details) - USD ($) |
Sep. 30, 2020 |
Dec. 31, 2019 |
|---|---|---|
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
| Past due loans | $ 3,920,000 | $ 7,523,000 |
| Loans past due greater than 30 days [Member] | ||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
| Past due loans | $ 3,535,000 | |
| Guaranteed student loans [Member] | Loans past due greater than 30 days [Member] | ||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
| Percentage of recovery | 98.00% |