Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
Consolidated Balance Sheets [Abstract]
Common stock, par value	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000	200,000,000
Common stock, shares issued	66,569,000	68,635,000	69,452,000
Common stock, shares outstanding	66,569,000	68,635,000	69,452,000
Treasury stock, shares	7,416,000	5,148,000	4,070,000