Guarantees (Tables)

9 Months Ended

Sep. 30, 2013

Changes in the warranty obligation which is included as a component of “Other accrued liabilities” on the condensed consolidated balance sheets during the periods are as follows (in thousands):

	Three Months Ended
	September 30, 2013			September 30, 2012				September 30, 2013				September 30, 2012
Balance at beginning of period	$	9,686		$	9,950		$		10,475		$		10,577
Accruals for warranties issued during the period		4,295			5,376				12,407				14,839
Actual charges against warranty reserve during the period		(4,270	)		(4,848	)			(13,171	)			(14,938	)
Balance at end of period	$	9,711		$	10,478		$		9,711		$		10,478

Changes in Deferred Service Revenues

Changes in the three and nine months ended September 30, 2013 and 2012 are as follows (in thousands):

	Three Months Ended							Nine Months Ended
	September 30, 2013			September 30, 2012				September 30, 2013				September 30, 2012
Balance at beginning of period	$	252,091		$	229,615		$		241,773		$		212,178
Additions to deferred services revenue		87,993			86,157				268,392				258,777
Amortization of deferred services revenue		(86,114	)		(80,259	)			(256,195	)			(235,442	)
Balance at end of period	$	253,970		$	235,513		$		253,970		$		235,513