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Related Party Transactions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Prior Owner | Other Liabilities
Related Party Transactions
Investment partnerships with prior owners	$ 49,700,000	$ 61,200,000
Affiliated Entity
Related Party Transactions
Imputed interest expenses of contingent payment arrangements	600,000	6,600,000
Affiliated Entity | Other Liabilities
Related Party Transactions
Contingent liabilities arrangements to related parties	1,900,000	9,400,000
Payments associated with contingent liabilities arrangements to related parties	$ 8,800,000	$ 6,800,000.0

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Amount of liability recognized arising from contingent consideration in a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
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Amount of cash outflow, not made soon after acquisition date of business combination, to settle contingent consideration liability exceeding amount recognized at acquisition date. Includes, but is not limited to, measurement period adjustment and less amount paid soon after acquisition date.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 230
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-Section 45
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