Stock Repurchases (Details) (USD $)			3 Months Ended
	Sep. 30, 2012	Mar. 26, 2012	Jun. 30, 2012 Open Market [Member]	Jun. 30, 2012 Tender Offer [Member]	Mar. 31, 2011 Tender Offer [Member]	Sep. 30, 2012 Senior Notes [Member]	Mar. 03, 2011 Senior Notes [Member]
Equity, Class of Treasury Stock [Line Items]
Increase in number of shares authorized for repurchase		1,000,000
Remaining number of shares authorized for repurchase	976,129
Common stock repurchased, shares			285,402	1,000,000	1,900,000
Common stock repurchased, value			$ 27,000,000	$ 84,500,000	$ 125,000,000
Tender offer, amount of shares for repurchase				1,000,000	1,900,000
Tender offer, share repurchase price per share				$ 84.45	$ 65.625
Senior notes principal amount						$ 350,000,000	$ 100,000,000