Other Income, net of expenses (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Component of Other Income, Nonoperating [Line Items]
Other Income, Net of expenses	$ 366	$ 122	$ 773	$ 610
Interest Income [Member]
Component of Other Income, Nonoperating [Line Items]
Other Income, Net of expenses	247	204	477	438
Gain (Loss) on Investments [Member]
Component of Other Income, Nonoperating [Line Items]
Other Income, Net of expenses	69	(19)	141	73
Other Nonoperating Income [Member]
Component of Other Income, Nonoperating [Line Items]
Other Income, Net of expenses	$ 50	$ (63)	$ 155	$ 99