The percentage of total net revenues generated by AFSC.

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- Definition

Represents the number of shares repurchased by the entity pursuant to the share repurchase program.

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No definition available.

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Aggregate cost of stock that was repurchased during the period, excluding broker commissions.

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No definition available.

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- Definition

The increase in amount authorized by an entity's board of directors under a stock repurchase plan.

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No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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- Definition

Amount of stock repurchase plan authorized.

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No definition available.

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Amount remaining of a stock repurchase plan authorized.

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No definition available.

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Total cost of shares repurchased divided by the total number of shares repurchased.

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Commitments and Contingencies (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	3 Months Ended		12 Months Ended			42 Months Ended
	May 24, 2018	Apr. 26, 2019	Mar. 31, 2019	Dec. 31, 2015	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2019	Oct. 26, 2015
Commitments and Contingencies
Percentage of total net revenues generated by AFSC			2.00%		2.00%
Maximum \| Pharmacy Management segment network provider pricing dispute
Commitments and Contingencies
Estimate of possible loss			$ 20.0					$ 20.0
Minimum \| Pharmacy Management segment network provider pricing dispute
Commitments and Contingencies
Estimate of possible loss			$ 0.0					$ 0.0
October 2015 Share Repurchase Program
Commitments and Contingencies
Amount authorized under stock repurchase plan	$ 400.0								$ 200.0
Increase in amount authorized under stock repurchase plan	$ 200.0
Share repurchases made in open market (in shares)		0	60,901	345,044	844,872	280,140	1,828,183	3,359,140
Average Price Paid per Share (in dollars per share)			$ 61.15	$ 53.46	$ 74.59	$ 77.67	$ 58.40
Aggregate Cost			$ 3.7	$ 18.4	$ 63.0	$ 21.8	$ 106.8	$ 213.7
Remaining authorized repurchase amount			$ 186.3					$ 186.3