Schedule II - Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Accounts receivable allowance [Member]	Dec. 31, 2010 Accounts receivable allowance [Member]	Dec. 31, 2011 Accounts and notes receivable allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 583	$ 3,674	$ 1,185
Charged to Costs and Expenses, Additions	240	(409)	(160)
Charged to Other Accounts, Additions	0	0	0
Uncollectible Accounts Written-off	83	2,080	442
Balance at End of Period	$ 740	$ 1,185	$ 583