Accumulated Other Comprehensive Income (Schedule of Reclassification out of Accumulated Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of investments	$ 2,059	$ 0	$ 2,059	$ 0
Provision for income taxes	(3,245)	(1,406)	(4,404)	(2,950)
Consolidated net income	3,280	3,597	5,768	7,366
Amount Reclassified from Accumulated Other Comprehensive Income | Unrealized Holding Gains (Losses) on Available-for-Sale Investments
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of investments	804		804
Provision for income taxes	(136)		(136)
Consolidated net income	$ 668		$ 668