Significant Accounting Policies Deferred Revenue (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 85,600,000	$ 63,500,000	$ 81,600,000	$ 59,900,000
New contracts sold	13,200,000	9,900,000
Less: reductions for revenue recognized	(9,200,000)	(6,300,000)
Deferred Revenue, Current	35,800,000	27,200,000
Deferred Revenue, Noncurrent	$ 49,800,000	$ 36,300,000