Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Noncash or Part Noncash Acquisitions [Line Items]
Interest	$ 7,149	$ 4,072	$ 4,338
Income taxes	5,810	9,838	5,845
Total interest and income taxes paid	12,959	13,910	10,183
Series of Business Acquisitions | Common Stock
Noncash or Part Noncash Acquisitions [Line Items]
Buildings - Build to Suit Leases	48,428	0	0
Repurchases of common stock	0	91	0
Shares issued as payment of contingent consideration	0	4,678	2,012
Total shares issued for acquisition and contingent consideration	$ 48,428	$ 4,769	$ 2,012