Supplemental Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Supplemental disclosure:
Income taxes paid	$ 9,850	$ 5,904	$ 10,533	$ 6,089
Non-cash investing and financing activities:
Non-cash capital expenditures	$ 262	$ 274	$ 264	$ 290