Investments in Debt and Equity Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Debt securities according to their contractual terms
Amortized costs, In one year or less	$ 11,763
Amortized costs, After one year through five years	223,740
Amortized costs, After five years through ten years	188,765
Amortized costs, After ten years	26,025
Amortized costs, Total	450,293
Fair Values, In one year or less	11,881
Fair Values, After one year through five years	228,916
Fair Values, After five years through ten years	203,619
Fair Values, After ten years	28,507
Debt securities, fair values total	$ 472,923