SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deducted from asset accounts Allowance for doubtful accounts
Changes in valuation and qualifying accounts
Balance at Beginning of Year	$ 2,969	$ 2,805	$ 3,002
Additions Charged to Costs and Expenses	492	441	380
Reductions	(884)	(277)	(577)
Balance at End of Year	2,577	2,969	2,805
Deducted from asset accounts Deferred tax valuation account
Changes in valuation and qualifying accounts
Balance at Beginning of Year	318		369
Acquired through Central Merger	24,981
Reductions			(51)
Balance at End of Year	25,299		318
Long-term receivables valuation allowance
Changes in valuation and qualifying accounts
Balance at End of Year	$ 2,484