Components of Deferred Income Tax Amounts (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred Income Tax Assets
Provision for bad debts	$ 8,012	$ 7,585
Employee retirement and other benefit obligations	72,227	62,637
Workers' compensation	9,538	10,007
Deferred compensation	12,067	10,895
Credits and net operating loss carryforwards	49,556	48,609
Other	25,953	23,781
Total deferred income tax assets	177,353	163,514
Deferred Income Tax Liabilities
Amortization of intangible assets	(23,305)	(22,169)
Property and equipment basis differences	(8,098)	(8,029)
Other	(6,626)	(5,257)
Total deferred income tax liabilities	(38,029)	(35,455)
Valuation allowance	(37,044)	(39,310)
Total deferred income tax assets, net	$ 102,280	$ 88,749