Income Taxes - Reconciliation of the Beginning and Ending Balances of our Liability for Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unrecognized tax benefits
Balance, beginning of year	$ 1,540	$ 1,668	$ 1,915
Purchase accounting adjustment related to acquisitions	160
Lapse of statute of limitations	(313)	(420)	(226)
Additions for tax positions of prior years	111	322	85
Reductions for tax positions of prior years	(105)	(30)	(106)
Balance, end of year	$ 1,393	$ 1,540	$ 1,668