Debt (Details) - Jun. 30, 2015 - Senior Subordinated Convertible Notes [Member] $ / shares in Units, $ in Millions	USD ($) shares NotesConverted $ / shares
Debt Instrument [Line Items]
Stated Interest Rate Percentage - Debt Instruments (in hundredths)	3.75%
Maturity year of Senior subordinated convertible notes	2034
First Conversion Date	Jan. 15, 2009
Number of Notes Converted | NotesConverted	7,822
Cash Payments for Debt Conversions (in millions)	$ 16.6
Deferred Tax Liability (in millions)	$ 0.8
Per Note Conversion Price (in dollars per share) | $ / shares	$ 502.13
Principal note amount (in millions)	$ 4.0
Excess above Principal Note Amount (in millions)	$ 14.0
If converted, issuance of common stock shares (in shares) | shares	82,565