Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental non-cash investing and financing activities:
Value of common stock issued in acquisition	$ 0	$ 3,268
Value of common stock issued in payment of accrued liability	188	0
Exercise of stock options by common stock surrender	5,863	50
Supplemental cash payment information:
Interest paid	1,511	1,459
Income taxes received, net of payments (paid, net of refunds)	$ 10,081	$ (1,663)