Financial Instruments and Fair Value Measurements (Financial Assets that are Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Sep. 30, 2016
Total financial assets	$ 94,293	$ 100,717
Fair Value, Inputs, Level 1 [Member]
Total financial assets	94,293	100,717
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	71,314	80,959
Cash [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	71,314	80,959
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	0	48
Investments in Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	0	48
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	167	83
Investments in Reverse Repurchase Agreements [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	167	83
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
Investments in Term Deposits with Foreign Banks [Member]
Cash and cash equivalents	7,472	7,136
Investments in Term Deposits with Foreign Banks [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	7,472	7,136
Investments in Term Deposits with Foreign Banks [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	0	0
Investments in Term Deposits with Foreign Banks [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	0	0
Equity Securities [Member]
Equity securities	15,340	12,491
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Equity securities	15,340	12,491
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