Fair Value Measurements (Marketable Equity and Cash Equivalents (Classified as Available-for-sale) and Cost Method Investments) (Details) (Fair Value, Inputs, Level 1, USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 29,401	$ 43,198
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	29,401	43,198
Money market instruments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,326	22,519
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	9,326	22,519
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,075	20,679
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	20,075	20,679
Cash and Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,970
Gross Unrealized Holding Gains	0
Gross Unrealized Holding Losses	0
Fair Value	27,970
Cash and Cash Equivalents and Restricted Cash
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		41,721
Gross Unrealized Holding Gains		0
Gross Unrealized Holding Losses		0
Fair Value		41,721
Short-term Investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,431	1,477
Gross Unrealized Holding Gains	0	0
Gross Unrealized Holding Losses	0	0
Fair Value	$ 1,431	$ 1,477