Capital Stock (Details) (USD $)	1 Months Ended		12 Months Ended				12 Months Ended				12 Months Ended				1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended			1 Months Ended	0 Months Ended		0 Months Ended		12 Months Ended			0 Months Ended	1 Months Ended	12 Months Ended
	Jul. 31, 2012	May 31, 2011	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2013 2006 Plan and 2004 Director Plan	Jun. 30, 2013 2006 Plan	Jun. 30, 2012 2006 Plan	Jun. 30, 2011 2006 Plan	Nov. 13, 2012 2006 Plan	Jun. 30, 2013 2006 Plan Stock options	Jun. 30, 2012 2006 Plan Stock options	Jun. 30, 2011 2006 Plan Stock options	Nov. 30, 2001 2001 Director Plan	Nov. 30, 2011 2001 Director Plan Deferred share units	Jun. 30, 2013 2001 Director Plan Deferred share units	Jun. 30, 2012 2001 Director Plan Deferred share units	Jun. 30, 2011 2001 Director Plan Deferred share units	Jun. 30, 2004 2004 Director Plan Deferred share units	Jun. 30, 2013 2004 Director Plan Deferred share units	Jun. 30, 2012 2004 Director Plan Deferred share units	Jun. 30, 2011 2004 Director Plan Deferred share units	Sep. 30, 2006 2004 Amended Director Plan Deferred share units	Nov. 11, 2009 Compensation Policy for Non-Employee Directors Initial equity grant upon election to the Board	Nov. 11, 2009 Compensation Policy for Non-Employee Directors Equity grant on first anniversary of initial election to the board	Nov. 11, 2009 Compensation Policy for Non-Employee Directors Annual equity grant	Sep. 22, 2010 Compensation Policy for Non-Employee Directors Stock options	Jun. 30, 2013 Compensation Policy for Non-Employee Directors Stock options	Jun. 30, 2012 Compensation Policy for Non-Employee Directors Stock options	Jun. 30, 2011 Compensation Policy for Non-Employee Directors Stock options	Nov. 11, 2009 Compensation Policy for Non-Employee Directors Deferred share units	Nov. 30, 2011 Compensation Policy for Non-Employee Directors Deferred share units item	Jun. 30, 2013 Compensation Policy for Non-Employee Directors Deferred share units	Jun. 30, 2012 Compensation Policy for Non-Employee Directors Deferred share units	Jun. 30, 2011 Compensation Policy for Non-Employee Directors Deferred share units
Sale of Common Stock
Issuance of common stock through a public offering (in shares)	6,250,000	7,800,000
Price at which common stock is issued through a public offering (in dollars per share)	$ 16.00	$ 12.00
Gross proceeds from issuance	$ 100,000,000	$ 93,600,000	$ 93,991,000		$ 87,980,000
Stock-based Compensation
Aggregate number of common shares reserved for future issuance						12,570,000
Options exercised (in shares)											666,000
Exercise price (in dollars per share)											$ 2.91
Exercise price (in dollars per share)											$ 15.20
Proceeds from stock options exercised			4,026,000	6,988,000	2,719,000						4,026,000	6,988,000	2,719,000
Exercisable (in shares)											4,202,000	3,416,000	3,834,000
Weighted-Average Exercise Price (in dollars per share)											$ 7.97	$ 6.34	$ 5.25
Common stock reserved for grant (in shares)										12,000,000				50,000
(Expense reduction) compensation expense							12,400,000	9,900,000	5,500,000							(1,000)	29,000	44,000															351,000	314,000	326,000
Stock units outstanding (in shares)																6,000	6,000	15,000
Payment to retiring director to settle outstanding stock units															115,000
Monthly vesting rights (as a percent)																			8.30%
Vesting period																							3 years	3 years		1 year	1 year
Aggregate market value of award																								65,000	30,000	30,000
Maximum vesting period from the date units were credited to the non-employee director for the award to be vested on September 16, 2009																			1 year
Number of shares of common stock issued under 2009 Compensation Policy for each vested deferred stock unit held on the date a director ceases to be a member																															1
Number of retiring directors to whom common stock is issued																																2
Grant date fair value																											$ 30,000
Stock options granted to directors (in shares)											2,047,000																	41,805	33,187	49,688
Stock units issued																				251,000	264,000	225,000											26,000	33,000	39,000
Common stock issued to settle retiring directors' share units																																46,298