Supplemental Disclosure of Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Supplemental Cash Flow Information [Abstract]
Interest paid	$ 1,612	$ 1,548	$ 1,908	$ 2,057
Income taxes paid	$ 10,827	$ 6,304	$ 13,282	$ 6,373