Financial Instruments (Details) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Fair Value Balance Sheet Grouping Financial Statement Captions [Abstract]
Accounts receivable, net, Carrying amount	$ 66,438,000	$ 58,976,000
Accounts receivable, net, Fair value	66,438,000	58,976,000
Accounts payable, Carrying amount	15,697,000	14,334,000
Accounts payable, Fair value	15,697,000	14,334,000
Debt:
Variable-rate debt, Carrying amount	36,899,000	33,630,000
Variable-rate debt, Fair value	36,899,000	33,630,000
Fixed-rate debt, Carrying amount	1,007,000	984,000
Fixed-rate debt, Fair value	1,046,000	1,029,000
Financial Instruments (Textual) [Abstract]
Non-interest bearing note	$ 1,100,000	$ 1,100,000