Equity Securities and Stock-Based Compensation (Details) (USD $) Share data in Thousands, unless otherwise specified	1 Months Ended	3 Months Ended			6 Months Ended
	Feb. 29, 2012	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Equity Securities and Stock-Based Compensation
Common stock, shares issued			11,500
Gross proceeds from issuance of common stock			$ 83,400,000
Offering costs			5,400,000		5,418,000
Net proceeds from issuance of common stock			78,000,000		77,957,000	0
Amount available for future offerings of securities	210,000,000		126,600,000
Treasury stock and related deferred compensation obligation at fair value		500,000			500,000
Amount that the fair values of treasury stock and related deferred compensation obligation exceed the carrying values at cost.		200,000			200,000
Stock-based compensation		400,000		300,000	821,000	923,000
Total compensation cost related to unvested awards not yet recognized		$ 2,100,000			$ 2,100,000