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Employee Benefit Plans (Fair Value and Allocation Of Plan Assets) (Details) - USD ($) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Oct. 01, 2014 | Dec. 31, 2013
BancShares Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 550,025 | $ 544,956 |  | $ 524,017
Actual % of Plan Assets | 100.00% | 100.00% |  |
BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 550,025 | $ 544,956 |  |
BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 469,647 | 391,028 |  |
BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 80,378 | 153,928 |  |
BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Bancorporation Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 150,893 | 155,618 | $ 150,374 | $ 0
Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 150,893 | 155,618 |  |
Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 126,392 | 143,938 |  |
Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 24,501 | 11,680 |  |
Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 | $ 0 |  |
Cash and equivalents | BancShares Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Actual % of Plan Assets | 5.00% | 1.00% |  |
Cash and equivalents | BancShares Plan | Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 0.00% | 0.00% |  |
Cash and equivalents | BancShares Plan | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 1.00% | 1.00% |  |
Cash and equivalents | BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 26,613 | $ 3,854 |  |
Cash and equivalents | BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 26,613 | 3,854 |  |
Cash and equivalents | BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Cash and equivalents | BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 | $ 0 |  |
Cash and equivalents | Bancorporation Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Actual % of Plan Assets | 8.90% | 8.40% |  |
Cash and equivalents | Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 13,437 | $ 13,077 |  |
Cash and equivalents | Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 13,437 | 13,077 |  |
Cash and equivalents | Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Cash and equivalents | Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 | $ 0 |  |
Equity Securities | BancShares Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Actual % of Plan Assets | 63.00% | 62.00% |  |
Equity Securities | BancShares Plan | Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 55.00% | 55.00% |  |
Equity Securities | BancShares Plan | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 65.00% | 65.00% |  |
Equity Securities | BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 267,037 | $ 284,656 |  |
Equity Securities | BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 267,037 | 284,656 |  |
Equity Securities | BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Equity Securities | BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 | $ 0 |  |
Equity Securities | Bancorporation Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 60.00% |  |  |
Actual % of Plan Assets | 63.00% | 69.00% |  |
Equity Securities | Bancorporation Plan | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 70.00% |  |  |
Equity Securities | Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 80,676 | $ 101,540 |  |
Equity Securities | Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 80,676 | 101,540 |  |
Equity Securities | Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Equity Securities | Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 | $ 0 |  |
Debt Securities | BancShares Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Actual % of Plan Assets | 26.00% | 28.00% |  |
Debt Securities | BancShares Plan | Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 25.00% | 25.00% |  |
Debt Securities | BancShares Plan | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 40.00% | 40.00% |  |
Debt Securities | Bancorporation Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Actual % of Plan Assets | 22.00% | 23.00% |  |
Equity mutual funds | BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 78,645 | $ 52,379 |  |
Equity mutual funds | BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 78,645 | 52,379 |  |
Equity mutual funds | BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Equity mutual funds | BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Equity mutual funds | Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 15,005 | 5,793 |  |
Equity mutual funds | Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 15,005 | 5,793 |  |
Equity mutual funds | Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Equity mutual funds | Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
US government and government agency securities | BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 58,526 | 23,528 |  |
US government and government agency securities | BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 48,957 | 23,528 |  |
US government and government agency securities | BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 9,569 | 0 |  |
US government and government agency securities | BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
US government and government agency securities | Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 20,476 |  |  |
US government and government agency securities | Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 3,986 |  |  |
US government and government agency securities | Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 16,490 |  |  |
US government and government agency securities | Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 |  |  |
Corporate Bonds | BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 70,809 |  |  |
Corporate Bonds | BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 |  |  |
Corporate Bonds | BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 70,809 |  |  |
Corporate Bonds | BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 |  |  |
Corporate Bonds | Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 8,011 | 11,680 |  |
Corporate Bonds | Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Corporate Bonds | Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 8,011 | 11,680 |  |
Corporate Bonds | Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Fixed Income Mutual Funds | BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 17,351 | 153,928 |  |
Fixed Income Mutual Funds | BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 17,351 | 0 |  |
Fixed Income Mutual Funds | BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 153,928 |  |
Fixed Income Mutual Funds | BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | $ 0 |  |
Fixed Income Mutual Funds | Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 4,198 |  |  |
Fixed Income Mutual Funds | Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 4,198 |  |  |
Fixed Income Mutual Funds | Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 |  |  |
Fixed Income Mutual Funds | Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 |  |  |
Alternative investments | BancShares Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Actual % of Plan Assets | 6.00% | 9.00% |  |
Alternative investments | BancShares Plan | Minimum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 0.00% | 0.00% |  |
Alternative investments | BancShares Plan | Maximum |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 10.00% | 8.00% |  |
Alternative investments | BancShares Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 31,044 | $ 50,139 |  |
Alternative investments | BancShares Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 31,044 | 50,139 |  |
Alternative investments | BancShares Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 | 0 |  |
Alternative investments | BancShares Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 | $ 0 |  |
Alternative investments | Bancorporation Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Actual % of Plan Assets | 6.00% |  |  |
Defined Benefit Plan, Target Allocation Percentage | 0.05 |  |  |
Alternative investments | Bancorporation Plan | Fair Value |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 9,090 |  |  |
Alternative investments | Bancorporation Plan | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 9,090 |  |  |
Alternative investments | Bancorporation Plan | Quoted Prices for Similar Assets and Liabilities (Level 2 Inputs) |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | 0 |  |  |
Alternative investments | Bancorporation Plan | Fair Value, Inputs, Level 3 |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Plan assets | $ 0 |  |  |
Fixed Income And Cash | Bancorporation Plan |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Target Allocation | 35.00% |  |  |

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- Definition Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=49178875&loc=d3e12355-114930 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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