Fair Value Measurements (Details) (Recurring [Member], USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Level 1 [Member]
Fair value assets
Mutual funds	$ 14,836	$ 13,960	$ 10,787
Equities	8,413	9,336	7,236
Total asset	23,249	23,296	18,023
Level 2 [Member]
Fair value assets
Medium-term investments	0	0	3,910
Common/collective trust funds	1,368	2,431	3,185
Total asset		2,431	1,481
Fair value liabilities
Interest rate swaps	(7,419)	0	(5,614)
Net liability	$ (6,051)

Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents investment securities as of the balance sheet date which may include marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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