Cash and Cash Equivalents and Short-term Investments (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	$ 17,550
Available-for-sale securities, more than 12 months	546
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	2,276
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	90
Available-for-sale equity securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	16,622
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	2,272
Available-for-sale debt securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	928
Available-for-sale securities, more than 12 months	546
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	4
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	90
Mortgage-CMO debt securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	109
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	3
Asset-backed debt securities
Gross unrealized losses of cash and cash equivalents and short-term investments
Available-for-sale securities, less than 12 months	819
Available-for-sale securities, more than 12 months	546
Available-for-sale securities, continuous unrealized loss position, less than 12 Months, aggregate losses	1
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, aggregate losses	$ 90