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Business Segments Total Assets by Segment (Details) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |
Assets |  | $ 2,941.4 | $ 2,687.8
Apex |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |
Assets |  | 1,504.5 | 1,368.5
Oxford |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |
Assets |  | 433.8 | 421.2
ECS |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |
Assets |  | 935.2 | 865.6
Corporate |  |  |
Segment Reporting, Asset Reconciling Item [Line Items] |  |  |
Assets | [1] | $ 67.9 | $ 32.5
[1] | Corporate segment assets include workers’ compensation receivable and rabbi trust assets related to deferred compensation for employees of other segments. These programs are managed by the Company's corporate office and the related balances are recorded at corporate. These assets have offsetting liabilities for workers' compensation loss reserves and the Company's deferred compensation plan.

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