Basis of Presentation and Summary of Significant Accounting Policies (Schedule of Unrealized Losses and Fair Values by Investment Category and Time in Continuous Unrealized Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than Twelve Months, Fair Value	$ 60,782
Less than 12 Months, Unrealized Losses	(390)
Twelve Months or More, Fair Value	1,048
12 Months or More, Unrealized Losses	(4)
Fair Value, Total	61,830
Unrealized Losses, Total	(394)
U.S. Corporate Debt Securities
Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]
Less than Twelve Months, Fair Value	60,782
Less than 12 Months, Unrealized Losses	(390)
Twelve Months or More, Fair Value	1,048
12 Months or More, Unrealized Losses	(4)
Fair Value, Total	61,830
Unrealized Losses, Total	$ (394)