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Summary of Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax | $ 5,176 | $ 11,667 | $ 10,943
Other Tax Expense (Benefit) | $ 1,812 | 4,083 | 3,830
Acquisition Costs Amortization In Years For Individual Life Contracts Term One | 10 years |  |
Acquisition Costs Amortization In Years For Individual Life Contracts Term Two | 15 years |  |
Acquisition Costs Amortization In Years For Individual Life Contracts Term Three | 20 years |  |
Acquisition Costs Amortization In Years For Individual Life Contracts Term Four | 30 years |  |
Amortization Period Of Acquisition Costs Related To Property And Casualty Policy Term One | 6 months |  |
Amortization Period Of Acquisition Costs Related To Property And Casualty Policy Term Two | 12 months |  |
Percentage Of Reversion To Mean Approach Utilized To Amortize Policy Acquisition Costs | 10.00% |  |
Federal Home Loan Bank Advances Branch Off hlb Bank Borrowings Description | Any borrowing from the FHLB requires the purchase of FHLB activity-based common stock in an amount equal to 5.0% of the borrowing, or a lower percentage such as 2.0% based on the Reduced Capitalization Advance Program. |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate | 0.52% |  |
Allocated Share-based Compensation Expense | $ 1,207 | 1,285 | 1,270
Weighted Average Fair Value Of Nonvested Options Outstanding | $ 6.82 |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 413,406 |  |
Earnings Per Share, Potentially Dilutive Securities | $31.01 to $36.04 |  |
Federal Home Loan Bank Advances Branch Of FHLB Bank Additional Amount Of Advances By Branch | $ 75,000 |  |
Un Allocated Share Based Compensation Expense | $ 9,517 |  |
Acquisition Costs Amortization In Years For Indexed Universal Life Contracts | 30 years |  |
Acquisition Costs Amortization In Years For Annuity Contracts | 20 years |  |
Other Assets | $ 321,874 | 292,139 |
Long-term Debt, Total | 247,209 | 246,975 |
Liabilities, Total | 9,282,842 | 8,792,311 |
Liabilities and Equity, Total | 10,576,824 | 10,056,972 |
Other Policy Holder Fund | $ 708,950 | 692,652 |
Percentage Of Credit Losses On Available For Sale Debt Securities To Total Investment Portfolio | 90.00% |  |
Federal Home Loan Bank Borrowings [Member] |  |  |
Other Policy Holder Fund | $ 575,000 |  |
Restatement Adjustment [Member] |  |  |
Other Assets |  | 2,371 |
Long-term Debt, Total |  | 2,371 |
Liabilities, Total |  | 2,371 |
Liabilities and Equity, Total |  | 2,371 |
Nonvested [Member] |  |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total | 2,299 |  |
Restricted Stock Units (RSUs) [Member] |  |  |
Allocated Share-based Compensation Expense | 6,929 | 892 | $ 6,132
Maturing On December 15, 2023 [Member] |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances | 125,000 |  |
Maturing On September 13, 2019 [Member] |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances | 250,000 |  |
Maturing On January 16, 2026 [Member] |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances | $ 200,000 |  |
Maximum [Member] |  |  |
Reserve Investment Yield Assumption Life | 3.50% |  |
Minimum [Member] |  |  |
Reserve Investment Yield Assumption Life | 8.00% |  |
Lease hold Improvements And Other Property And Equipment [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment, Useful Life | 10 years |  |
Lease hold Improvements And Other Property And Equipment [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment, Useful Life | 2 years |  |
Real Estate Property [Member] | Maximum [Member] |  |  |
Property, Plant and Equipment, Useful Life | 45 years |  |
Real Estate Property [Member] | Minimum [Member] |  |  |
Property, Plant and Equipment, Useful Life | 20 years |  |
Investment Contracts [Member] |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances | $ 575,000 |  |
Interest Sensitive Life Contracts [Member] |  |  |
Deferred Policy Acquisition Cost Ending Impact Of Unrealized Investment Gains Losses | $ 40,274 | $ 38,819 |
Amortization Period Of Acquisition Costs Related To Interest Sensitive Life Contracts | 20 years |  |

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