Retirement Benefit Plans (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Jan. 31, 2019	Feb. 29, 2016	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Employer matching contribution percentage	50.00%	100.00%
Percent of employees' gross pay matched	2.00%	3.00%
Expense related to contributions			$ 2.3	$ 2.0	$ 1.5

Amount of cost for defined contribution plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration