Investments in Debt and Equity Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Debt securities according to their contractual terms
Amortized costs, In one year or less	$ 37,520
Amortized costs, After one year through five years	178,818
Amortized costs, After five years through ten years	195,208
Amortized costs, After ten years	24,644
Amortized costs, Total	436,190
Fair Values, In one year or less	37,764
Fair Values, After one year through five years	182,546
Fair Values, After five years through ten years	206,430
Fair Values, After ten years	27,343
Debt securities, fair values total	$ 454,083