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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits. Assets include, but are not limited to, stocks, bonds, other investments, earnings from investments, and contributions by the employer and employees.

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The number of employer shares or related party shares included in plan assets.

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Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Benefit liability other supplement retirement plans

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Minimum range of eligible compensation for noncontributory profit sharing feature.

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Owner occupied and commercial real estate loans, unamortized premiums.

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Rate of employee contribution from earnings

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Retirement Plans (Narrative) (Details) $ in Thousands	12 Months Ended
Retirement Plans (Narrative) (Details) $ in Thousands	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 4,000
Owner Occupied And Commercial Real Estate Loans Unamortized Premiums	16,000	$ 20,000
Benefit liability other supplement retirement plans	$ 6,000	6,400
Shares of company common stock \| shares	233,849
Rate of employee contribution from earnings	80.00%
Matching contribution allocation rate first time	100.00%
Employee contribution rate for first time matching	3.00%
Matching contribution allocation rate second time	50.00%
Employees contribution rate for second time matching	2.00%
Employer contribution in common stock	$ 26,100	25,500
Minimum range of eligible compensation for noncontributory profit sharing feature	0.00%
Maximum range of eligible compensation for noncontributory profit sharing feature	4.00%
Accrued profit sharing expense	$ 11,000	$ 6,000	$ 6,000
Contribution rate of profit sharing expenses	0.0175	0.01	0.01
Limited Partnerships, Capital Commitment	$ 9,000
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation percentage in equity	65.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation percentage in equity	30.00%
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Target investment allocation percentage in equity	5.00%
Limited Liability Partnerships [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	$ 4,000	$ 5,000
Common Stock [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	12,000	10,000
Common Stock [Member] \| Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	97,000	92,000
Debt [Member] \| Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	31,000	29,000
Real Estate Investment [Member] \| Insurance Company Pooled Separate Accounts [Member]
Defined Benefit Plan [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	$ 8,000	$ 8,000