Stock-Bases Compensation Plans - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2009	Dec. 31, 2011 Year	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2005	Dec. 31, 2011 Restricted Stock Units (RSUs)	Dec. 31, 2010 Restricted Stock Units (RSUs)	Dec. 31, 2009 Restricted Stock Units (RSUs)	Dec. 31, 2005 Restricted Stock Units (RSUs)	Dec. 31, 2004 Restricted Stock Units (RSUs)	Dec. 31, 2003 Restricted Stock Units (RSUs)	Dec. 31, 2010 Pacific Compensation Corporation
Schedule of Share based Compensation Arrangements by Share based Payment Award, Equity Instruments, Other Than Options, Restricted Stock Units [Line Items]
Compensation expense recognized		$ 2.8	$ 6.5	$ 6.9		$ 26.2	$ 29.6	$ 36.9
Income tax benefit related to share based compensation expense		1.0	2.3	2.4
Deferred tax benefit related to compensation expense						9.2	10.4	12.9
Fair value of common stocks issued to satisfy share based compensations		1.8	2.1	3.8
Compensation costs paid in cash		5.8	2.9	2.1
Options granted during the period		5,000			500
Restricted common shares outstanding						57,405
Restricted shares and units granted		5,000				2,500	2,500		250	33,972	23,433
Restricted shares and units granted, vesting period						1 year	1 year
Weighted-average grant-date fair value of options granted during the years		$ 133	$ 130	$ 98
Total intrinsic value of options exercised during the years		1.4	1.6	1.1
Unrecognized compensation costs related to non-vested stock-based compensation arrangements granted		0.8
Share based compensations vested during the period, total fair value		1.3	1.6	1.1
Unrecognized compensation costs related to non-vested stock-based compensation arrangements granted, period of recognition		1
Decrease in net earnings due to change in accounting	$ (3)
Percentage of common stock executives could purchase through exercise of options												5.00%
Stock option, vesting period												2 years
Stock option, expiration period												5 years