Earnings Per Share S-20 (Detail Level 4) (USD $) In Thousands, except Per Share data	3 Months Ended								12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2009
Net income	$ 36,574	$ 33,081	$ 36,045	$ 31,771	$ 29,984	$ 31,635	$ 29,977	$ 26,274	$ 137,471	$ 117,870	$ 103,102
Basic weighted average shares outstanding	86,335	86,218	85,770	85,469	85,325	84,694	84,341	83,870	84,558	84,558	84,118
Dilutive effect of stock options					823				739		712
Diluted weighted average shares outstanding	87,090	86,972	86,523	86,147	85,998	85,480	85,224	84,823	85,948	85,381	84,830
Basic net income per share	$ 0.42	$ 0.38	$ 0.42	$ 0.37	$ 0.35	$ 0.37	$ 0.36	$ 0.31	$ 1.60	$ 1.39	$ 1.23
Diluted net income per share	$ 0.42	$ 0.38	$ 0.42	$ 0.37	$ 0.35	$ 0.37	$ 0.35	$ 0.31	$ 1.59	$ 1.38	$ 1.22