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Statements of Cash Flows (Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands | 6 Months Ended
--- | ---
Jun. 30, 2019 | Jun. 30, 2018
Interest |  | $ 10,512 | $ 12,064
Federal income tax |  | 28,000 | 4,193
Operating cash flows from operating leases | [1] | 3,994 | 0
Operating cash flows from financing leases |  | 7 | 0
Financing cash flows from finance leases |  | 596 | 1,333
Assets acquired under finance lease arrangements |  | 814 | 0
Assets acquired under operating lease arrangements | [1] | 12,881 | 0
Non-cash purchase of property and equipment |  | 0 | 18
AFS Fixed Income Securities [Member] |  |  |
Corporate actions related to securities | [2] | $ 25,104 | $ 32,133
[1] | Upon adoption of ASU 2016-02, effective January 1, 2019, we are required to disclose cash paid for amounts included in the measurement of operating lease liabilities, as well as supplemental non-cash information on operating lease liabilities arising from obtaining operating lease assets.
[2] | Examples of such corporate actions include exchanges, non-cash acquisitions, and stock splits.

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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=98513485&loc=d3e4297-108586 + Details
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