Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Polsinelli
Related Party Transaction [Line Items]
Legal services obtained	$ 1.2	$ 0.0	$ 2.9	$ 0.6
Accounts payable for legal services	0.9	0.1	0.9	0.1
Family member of the Company's Executive Vice President \| Legal services from Segal McCambridge Singer & Mahone
Related Party Transaction [Line Items]
Legal services obtained	$ 0.2	$ 0.2	$ 0.5	$ 0.4

Amount for accounts payable to related parties.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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