Subsequent Events (Details) - $ / shares |
Feb. 17, 2021 |
Jan. 11, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|---|---|
| Subsequent Event [Line Items] | ||||
| Sub-share certificates of proprietary interest, par value (in dollars per share) | $ 0.0333 | $ 0.0333 | ||
| Certificates of proprietary interest, par value (in dollars per share) | $ 100 | $ 100 | ||
| Certificates of proprietary interest, outstanding (in shares) | 0 | 0 | ||
| Sub-share certificates of proprietary interest, outstanding (in shares) | 7,756,156 | 7,756,156 | ||
| Subsequent event | ||||
| Subsequent Event [Line Items] | ||||
| Sub-share certificates of proprietary interest, par value (in dollars per share) | $ 0.01 | |||
| Sub-share certificates of proprietary interest, outstanding (in shares) | 7,756,156 | |||
| Subsequent event | Dividend declared | ||||
| Subsequent Event [Line Items] | ||||
| Annual cash dividend | $ 2.75 |
| X | ||||||||||
- Definition Face amount or stated value per share of common stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The per share amount of a dividend declared, but not paid, as of the financial reporting date. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Face amount or stated value per share of preferred stock nonredeemable or redeemable solely at the option of the issuer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. No definition available.
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|