Pension Plan (Components Of Net Periodic Pension Expense Related To The Qualified And Non-Qualified Plans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Pension Plan [Abstract]
Service cost	$ 1,964	$ 1,563
Interest cost	1,598	1,524
Expected return on plan assets	(2,233)	(1,665)
Amortization of prior service cost	177	160
Amortization of actuarial loss	582	343
Total net periodic pension expense	2,088	1,925
Amortization of prior service cost	(177)	(160)
Amortization of actuarial loss	(582)	(343)
Other changes in plan assets and benefit obligations recognized in other comprehensive income	(759)	(503)
Total amount recognized in net periodic benefit cost and other comprehensive income (before tax)	$ 1,329	$ 1,422

The amount of gains or losses recognized in net periodic benefit cost.

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The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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The amounts in accumulated other comprehensive income related to prior service cost or credit expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

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The aggregate net gain (loss) recognized in other comprehensive income, including amounts arising during the period and reclassification adjustments of other comprehensive income as a result of being recognized as components of net periodic benefit cost for the period.

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The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.

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An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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