Allowance For Doubtful Accounts

12 Months Ended

Dec. 31, 2011

Allowance For Doubtful Accounts [Abstract]

Allowance For Doubtful Accounts

3. ALLOWANCE FOR DOUBTFUL ACCOUNTS

	Years ended December 31,
	2011			2010			2009
Balance, beginning of year	$	4,700		$	3,159		$	1,727
Provision		2,169			2,408			1,852
Amounts written off, net of recoveries		(2,284	)		(867	)		(420	)
Balance, end of year	$	4,585		$	4,700		$	3,159