SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Details) (Allowance for Accounts Receivable Losses, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for Accounts Receivable Losses
Allowance for Accounts Receivable Losses
Balance at Beginning of Period	$ 2,176	$ 2,503	$ 2,116
Additions Charged to Operations	1,155	95	388
Acquired		658	224
Write-offs (net)	(832)	(1,080)	(225)
Balance at End of Period	$ 2,499	$ 2,176	$ 2,503