Additional Details Related to Certain Balance Sheet Captions (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Other current assets:
Prepaid taxes	$ 31.8	$ 27.6
Prepaid expenses	47.3	44.6
Other	12.8	5.4
Total other current assets	91.9	77.6
Other assets:
Investments in joint ventures	38.3	37.2
Deposits for real-estate leases	10.0	12.2
Other	47.7	32.6
Total other assets	96.0	82.0
Accounts payable and accrued liabilities:
Salaries and benefits	79.2	67.5
Incentive compensation	162.6	114.1
Profit sharing contribution	12.6	7.1
Customer credits, advanced payments and advanced billings	21.5	17.6
Self-insurance reserves	55.8	27.1
Dividends	47.7	38.2
Professional service fees	30.2	29.7
Interest accrued on debt	23.4	15.1
Accounts payable	14.3	16.4
Income taxes (see Note 13)	56.1	23.4
Deferred rent-current portion	1.1	1.7
Pension and other retirement employee benefits (see Note 11)	4.4	3.8
Other	46.4	60.9
Total accounts payable and accrued liabilities	555.3	452.3
Other liabilities:
Pension and other retirement employee benefits (see Note 11)	213.3	187.5
Deferred rent-non-current portion	110.2	108.8
Legacy and other tax matters	37.1	52.6
Other	38.9	44.1
Total other liabilities	410.1	404.8
Accounts payable and accrued liabilities
Accounts payable and accrued liabilities:
Interest accrued on UTPs		29.7
Other liabilities:
Interest accrued on UTPs		29.7
Other Liabilities
Accounts payable and accrued liabilities:
Interest accrued on UTPs	10.6	11.8
Other liabilities:
Interest accrued on UTPs	$ 10.6	$ 11.8