Supplemental Cash Flow Information (Tables)

9 Months Ended

Sep. 30, 2013

Supplemental Cash Flow Elements [Abstract]

Supplemental Cash Flow Information

	Three months ended						Nine months ended
	September 30, 2013			September 30, 2012			September 30, 2013		September 30, 2012
Supplemental disclosures:	(in thousands)
Interest paid	$	1		$	24		$	1	$	50
Income taxes paid	8,915			7,500			15,004		11,200
Non-cash investing and financing activities:
Non-cash capital expenditures	(265		)	(1,723		)	25		(3,079		)
Trade-in of equipment	—			—			—		300