Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
401(K) Plan
Plan expense	$ 1.8	$ 2.1	$ 1.6
Eligible Compensation, 4%
401(K) Plan
Matching contribution, percent	100.00%
Eligible compensation, percent	4.00%
Eligible Compensation, 2%
401(K) Plan
Matching contribution, percent	50.00%
Eligible compensation, percent	2.00%