Marketable Investment Securities (Tables)

9 Months Ended

Mar. 31, 2019

Investments Debt And Equity Securities [Abstract]

Schedule of Fair Value for Available-for-Sale Securities by Major Security Type and Class of Security

The amortized cost, gross unrealized holding gains, gross unrealized holding losses, and fair value for available-for-sale securities by major security type and class of security at March 31, 2019 and June 30, 2018 were as follows:

			Gross		Gross
			unrealized		unrealized
	Amortized		holding		holding			Estimated
	cost		gains		losses			fair value
At March 31, 2019:
Cash and cash equivalents:
Cash	$	70.3	$	—	$	—		$	70.3
Cash equivalents		14.6		—		—		$	14.6
Total cash and cash equivalents		84.9		—		—			84.9
Available-for-sale:
Corporate bonds and notes		67.5		0.2		(0.1	)		67.6
Municipal bonds		18.1		—		—			18.1
Federal agency issues		12.1		—					12.1
US government securities		7.3		—		—			7.3
Total	$	189.9	$	0.2	$	(0.1	)	$	190.0

			Gross		Gross
			unrealized		unrealized
	Amortized		holding		holding			Estimated
	cost		gains		losses			fair value
At June 30, 2018:
Cash and cash equivalents:
Cash	$	95.6	$	—	$	—		$	95.6
Cash equivalents		15.3		—		—			15.3
Total cash and cash equivalents		110.9		—		—			110.9
Available-for-sale:
Corporate bonds and notes		50.8		—		(0.3	)		50.5
Municipal bonds		29.3		—		(0.1	)		29.2
Federal agency issues		12.6		—		(0.1	)		12.5
US government securities		8.3		—		(0.1	)		8.2
Total	$	211.9	$	—	$	(0.6	)	$	211.3

Schedule of Maturities of Debt Securities Classified as Cash Equivalents and Available-For-Sale Securities

Cash, cash equivalents, and maturities of debt securities classified as available-for-sale securities are as follows at March 31, 2019:

	Amortized		Estimated
	cost		fair value
Cash	$	70.3	$	70.3
Cash equivalents		14.6		14.6
Available-for-sale:
Due within one year		66.3		66.2
Due after one year through five years		38.7		38.9
Due after five years		—		—
Total	$	189.9	$	190.0