Cash and Cash Equivalents and Short-term Investments (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	$ 17,270
Available-for-sale securities, more than 12 months	19,831
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	2,470
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	2,060
Equity Securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	16,428
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	2,467
Debt Securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	842
Available-for-sale securities, more than 12 months	19,831
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	3
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	2,060
Corporate debt securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, more than 12 months	17,900
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	1,919
Mortgage-CMO debt securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	842
Available-for-sale securities, more than 12 months	45
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	3
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	1
Asset-backed debt securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, more than 12 months	1,886
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	$ 140