Debt (Details) - Senior Subordinated Convertible Notes [Member] $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($) shares NotesConverted $ / shares
Debt Instrument [Line Items]
Stated interest rate percentage - debt instruments	3.75%
Maturity date of debt	Jan. 15, 2034
First conversion date	Jan. 15, 2009
Number of notes converted | NotesConverted	564
Cash payments for debt conversions	$ 1.2
Deferred tax liability	$ 0.1
Per note conversion price (in dollars per share) | $ / shares	$ 521.19
Principal note amount	$ 4.0
Excess above principal note amount	$ 12.0
Common stock shares issuable on conversion of debt | shares	72,855