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Statements of Cash Flow (Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Interest | $ 30,464 | $ 25,089 | $ 23,992
Federal income tax | 47,000 | 55,825 | 29,193
Operating cash flows from operating leases | 9,498 | 8,138 | 0
Operating cash flows from financing leases | 15 | 16 | 0
Financing cash flows from financing leases | 550 | 977 | 5,646
Assets acquired under finance lease arrangements | 324 | 824 | 4,119
Assets acquired under operating lease arrangements | 22,390 | 13,808 | 0
Non-cash purchase of property and equipment | 590 | 89 | 291
Available-for-sale Securities [Member] |  |  |
Corporate actions related to securities | 55,446 | 61,369 | 52,277
Held-to-maturity Securities [Member] |  |  |
Corporate actions related to securities | 2,589 | 0 | 0
Equity Securities [Member] |  |  |
Corporate actions related to securities | $ 10,890 | $ 14,250 | $ 944

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- Definition Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities. + References No definition available. + Details
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- Definition Amount of interest paid on finance lease liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(1) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918643-209977 + Details
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- Definition Amount of cash outflow for principal payment on finance lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918643-209977 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(1) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980 + Details
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- Definition The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4297-108586 + Details
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- Definition The amount of fixed assets that an Entity acquires in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4313-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586 + Details
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- Definition The amount of investments that an Entity acquires in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4313-108586 + Details
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- Definition Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918643-209977 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(1) -URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980 + Details
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