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Nature of Operations and Summary of Significant Accounting Policies Other Investments (Details) | 12 Months Ended
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Dec. 31, 2020
Investment In Limited Partnerships Accounting Treatment [Line Items] |
Maximum ownership percentage that is not consolidated | 50.00%
Investment in corporations minimum ownership percentage for accounting for using the equity method | 20.00%
Investment in corporations maximum ownership percentage for accounting for at cost | 20.00%
Investment in limited partnerships maximum ownership percentage for accounting for at cost | 3.00%
Minimum |
Investment In Limited Partnerships Accounting Treatment [Line Items] |
Investment in limited partnerships ownership percentage for accounting for using the equity method | 3.00%
Maximum |
Investment In Limited Partnerships Accounting Treatment [Line Items] |
Investment in limited partnerships ownership percentage for accounting for using the equity method | 50.00%

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