Fair Value Measurements (Details) (Recurring [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Level 1 [Member]
Fair value assets
Mutual funds	$ 14,591	$ 13,536	$ 13,594
Equities	8,641	7,057	10,144
Total	23,232	20,593	23,738
Level 2 [Member]
Fair value assets
Common/collective trust funds	455	2,192	1,323
Total	$ 455	$ 2,192	$ 1,323

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

No definition available.

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant