Financial Instruments and Fair Value Measurements (Financial Assets that are Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Sep. 30, 2015
Total financial assets	$ 130,083	$ 92,085
Fair Value, Inputs, Level 1 [Member]
Total financial assets	130,083	92,085
Fair Value, Inputs, Level 2 [Member]
Total financial assets	0	0
Fair Value, Inputs, Level 3 [Member]
Total financial assets	0	0
Cash [Member]
Cash and cash equivalents	117,339	79,517
Cash [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	117,339	79,517
Cash [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
Cash [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Investments in Money Market Funds [Member]
Cash and cash equivalents	41	20
Investments in Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	41	20
Investments in Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
Investments in Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Investments in Reverse Repurchase Agreements [Member]
Cash and cash equivalents	739	2,665
Investments in Reverse Repurchase Agreements [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	739	2,665
Investments in Reverse Repurchase Agreements [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
Investments in Reverse Repurchase Agreements [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Equity Securities [Member]
Equity securities	11,964	9,883
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Equity securities	11,964	9,883
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Equity securities	0	0
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Equity securities	$ 0	$ 0