Additional Details Related to Certain Balance Sheet Captions (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Other current assets:
Prepaid taxes	$ 83.3	$ 65.4
Prepaid expenses	66.9	59.9
Other	29.4	47.2
Total other current assets	179.6	172.5
Other assets:
Investments in joint ventures	28.7	21.6
Deposits for real-estate leases	11.4	11.3
Indemnification assets related to acquisitions	19.2	23.5
Fixed maturity and other open ended mutual funds	55.0	48.0
Other	46.5	41.5
Total other assets	160.8	145.9
Accounts payable and accrued liabilities:
Salaries and benefits	83.8	86.5
Incentive compensation	$ 137.2	155.2
Profit sharing contribution		9.3
Customer credits, advanced payments and advanced billings	$ 24.6	17.0
Self-insurance reserves	19.7	21.5
Dividends	78.2	75.0
Professional service fees	54.5	47.0
Interest accrued on debt	59.4	45.0
Accounts payable	22.2	19.4
Income taxes (see Note 14)	11.5	16.1
Pension and other retirement employee benefits (see Note 11)	5.4	5.1
Other	70.1	60.5
Total accounts payable and accrued liabilities	566.6	557.6
Other liabilities:
Pension and other retirement employee benefits (see Note 12)	228.3	244.8
Deferred rent-non-current portion	98.4	104.2
Interest accrued on UTPs	27.9	20.8
Legacy and other tax matters	1.7	8.6
Other	60.9	52.5
Total other liabilities	$ 417.2	$ 430.9