Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net consolidated periodic pension cost
Service cost	$ 2,272	$ 2,127	$ 2,337
Interest cost	4,555	4,291	4,129
Expected return on plan assets	(8,343)	(7,138)	(5,328)
Amortization of transition asset	0	(131)	(175)
Recognized net actuarial loss	2,427	2,317	3,506
Amortization of prior service cost	1	1	1
Net periodic pension cost	$ 912	$ 1,467	$ 4,470
Weighted-Average Assumptions:
Discount rate	5.75%	6.25%	6.25%
Expected return on assets	8.00%	8.00%	8.00%
Rate of compensation increase	2.75%	2.75%	3.25%
Prior to age 45 [Member]
Weighted-Average Assumptions:
Rate of compensation increase	3.75%	3.75%	4.75%

Weighted Average Assumptions Discount Rate.

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- Definition

The net increase or decrease of changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

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The amounts in accumulated other comprehensive income related to transition assets (obligations), origination from the adoption of FAS 87 and 106, 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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- Definition

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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Expected rate of compensation increases (for pay-related plans).

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- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit 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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