Accrued Payroll and Benefit Costs (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Payroll and benefits	$ 214,292	$ 240,793
Employee deferred compensation plans	209,922	212,220
Workers’ compensation	27,350	25,834
Payroll taxes	21,152	25,935
Total accrued payroll costs and retirement obligations	472,716	504,782
Chief Executive Officer
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferred compensation plan and other benefits related to the Company’s Chief Executive Officer	$ 81,461	$ 81,874