Summary of Significant Accounting Policies (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Amortized cost and estimated fair value of debt and marketable equity securities
Amortized cost of equity securities	$ 31,596
Estimated fair value of equity securities	31,609
Due in one year or less [Member]
Amortized cost and estimated fair value of debt and marketable equity securities
Amortized cost of equity securities, Due in one year or less	23,125
Estimated fair value of equity securities	23,117
Due after one year through five years [Member]
Amortized cost and estimated fair value of debt and marketable equity securities
Amortized cost of equity securities, Due after one year through five years	8,479
Estimated fair value of equity securities, Due after one year through five years	$ 8,484