Other Balance Sheet Accounts - Other Current Assets (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Other Current Assets:
Non-trade receivables	$ 26.3	$ 28.4
Prepaid expenses and other current assets	11.7	13.8
Income taxes receivable	7.9	6.0
Marketable securities	0.4	0.4
Total other current assets	$ 46.3	$ 48.6

Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes.

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