Cash and Cash Equivalents and Investments (Details 2) (USD $) In Thousands	Sep. 30, 2011
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	$ 42,474
Available-for-sale securities, gross unrealized loss, less than 12 months	5,394
Available-for-sale securities, more than 12 months	2,810
Available-for-sale securities, gross unrealized loss, more than 12 months	256
Equity Securities [Member]
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	24,874
Available-for-sale securities, gross unrealized loss, less than 12 months	3,207
Available-for-sale securities, more than 12 months	0
Available-for-sale securities, gross unrealized loss, more than 12 months	0
Corporate debt securities [Member]
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	17,600
Available-for-sale securities, gross unrealized loss, less than 12 months	2,187
Available-for-sale securities, more than 12 months	0
Available-for-sale securities, gross unrealized loss, more than 12 months	0
Mortgage-CMO debt securities [Member]
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	0
Available-for-sale securities, gross unrealized loss, less than 12 months	0
Available-for-sale securities, more than 12 months	105
Available-for-sale securities, gross unrealized loss, more than 12 months	3
Asset-backed debt securities [Member]
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	0
Available-for-sale securities, gross unrealized loss, less than 12 months	0
Available-for-sale securities, more than 12 months	2,705
Available-for-sale securities, gross unrealized loss, more than 12 months	253
Debt Securities [Member]
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	17,600
Available-for-sale securities, gross unrealized loss, less than 12 months	2,187
Available-for-sale securities, more than 12 months	2,810
Available-for-sale securities, gross unrealized loss, more than 12 months	$ 256