Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental non-cash investing and financing activities:
Value of common stock issued in acquisitions	$ 0	$ 0	$ 3,268
Value of common stock issued in payment of accrued liability	0	188	0
Exercise of stock options by common stock surrender	0	5,863	50
Supplemental cash payment information:
Interest paid	2,502	1,851	2,024
Income taxes (received, net of payments) paid, net of refunds	$ (139)	$ (10,195)	$ 333