Stockholders' Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	6 Months Ended			1 Months Ended		1 Months Ended	12 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 09, 2009	Jun. 30, 2011 Year	Jun. 30, 2011 Stock Incentive Plan 2009	Aug. 13, 2009 Stock Incentive Plan 2009	Jan. 31, 2000 Stockholder Rights Plan	Jan. 31, 2000 Stockholder Rights Plan Series A Junior Participating Preferred Stock	Nov. 03, 2008 Stock Repurchase Program Year	Dec. 31, 2009 Stock Repurchase Program	Jun. 30, 2011 Stock Options	Jun. 30, 2010 Stock Options	Jun. 30, 2011 Stock Options	Jun. 30, 2010 Stock Options	Jun. 30, 2011 Restricted Stock Year	Jun. 30, 2010 Restricted Stock	Jun. 30, 2011 Restricted Stock	Jun. 30, 2010 Restricted Stock	Jun. 30, 2011 Minimum Year	Jun. 30, 2011 Maximum Year
Class of Stock [Line Items]
Common stock offered, shares	10,700,000
Common stock offered, price per share	$ 15
Net proceeds from offering of common stock	$ 152.8
Terms of stockholder rights plan					In January 2000, the Company's Board of Directors adopted a stockholder rights plan. Under the plan, each stockholder of common stock received a dividend of one right for each share of the Company's outstanding common stock, entitling the holder to purchase one thousandth of a share of Series A Junior Participating Preferred Stock, par value, $0.01 per share of the Company, at an initial exercise price of $6.00. The rights become exercisable and will trade separately from the common stock ten business days after any person or group acquires 15% or more of the common stock, or ten business days after any person or group announces a tender offer for 15% or more of the outstanding common stock. This plan expired by its terms on January 26, 2010.
Number of common stock shares authorized under Company's 2009 Equity Incentive Plan				3,000,000
Minimum percentage of acquisition of common stock to get the rights exercisable					15.00%
Minimum tender offer percentage of outstanding common stock to exercise right					15.00%
Plan expiration date			August 13,2019		January 26, 2010
Stockholders right to purchase series A preferred stock for each share of common stock						1,000
Series A Junior Participating Preferred Stock, par value						$ 0.01
Series A Junior Participating Preferred Stock, initial exercise price						$ 6.00
Repurchase of common stock authorized value							75
Period of common stock repurchase, years							3
Repurchase of common stock, shares								200,000
Repurchase of common stock, value								1.5
Expiration of repurchase plan								Oct. 30, 2011
Options grant, expected life		7															5	10
Compensation expense related to stock grants									0.2	0.1	0.2	0.1	2.5	2.3	4.8	4.5
Expected compensation expense related to restricted stock grants													17.6		17.6
Expected compensation expense recognition period, years													4
Shares withheld													$ 0.4	$ 0.5	$ 2.2	$ 0.5
Common shares reserved for issuance			364,234