Cash Dividends (Details) (USD $)	1 Months Ended		3 Months Ended		6 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011
Cash Dividends
Cash dividends, per share	$ 0.07	$ 0.07	$ 0.07	$ 0.06	$ 0.14	$ 0.12
Cash dividend paid, per share	$ 0.07