Restatement of Previously Issued Financial Statements (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 24, 2012	Jun. 26, 2011	Jun. 24, 2012		Jun. 26, 2011		Dec. 25, 2011	Dec. 26, 2010
As Previously Reported [Member]
Consolidated Statement of Stockholders' Equity
Retained earnings	$ 330,320	$ 271,703	$ 330,320		$ 271,703		$ 298,807	$ 243,152
Noncontrolling interests in subsidiaries	9,137	8,528	9,137		8,528		8,569	8,506
Total stockholders' equity	225,546	223,801	225,546		223,801		218,222	207,200
Condensed Consolidated Balance Sheet
Noncurrent deferred income tax liabilities	9,648	3,485	9,648		3,485		9,147
Long-term accrued income taxes	3,924		3,924
Other long-term liabilities	23,638	12,478	23,638		12,478		25,611
Retained earnings	330,320	271,703	330,320		271,703		298,807	243,152
Noncontrolling interests in subsidiaries	9,137	8,528	9,137		8,528		8,569	8,506
Total stockholders' equity	225,546	223,801	225,546		223,801		218,222	207,200
Condensed Consolidated Statement of Comprehensive Income
Interest expense	282	293	570		901
Income before income taxes	24,240	19,067	51,378		45,847
Income tax expense	8,299	6,014	17,367		15,245
Net income, including noncontrolling interests	15,941	13,053	34,011		30,602
Net income, net of noncontrolling interests	14,769	12,124	31,513		28,551
Comprehensive income	15,490	12,539	33,771		31,361
Basic earnings per common share	$ 0.62	$ 0.48	$ 1.32		$ 1.12
Earnings per common share - assuming dilution	$ 0.61	$ 0.47	$ 1.30		$ 1.11
Consolidated Statement of Cash Flows
Net income, including noncontrolling interests	15,941	13,053	34,011		30,602
Deferred income taxes			1,946		4,332
Other			2,480		316
Net cash provided by operating activities			65,162		52,925
Scenario, Adjustment [Member]
Consolidated Statement of Stockholders' Equity
Retained earnings	(4,249)	(3,593)	(4,249)		(3,593)		(4,006)	(3,086)
Noncontrolling interests in subsidiaries	(9,137)	(8,528)	(9,137)		(8,528)		(8,569)	(8,506)
Total stockholders' equity	(13,386)	(12,121)	(13,386)		(12,121)		(12,575)	(11,592)
Condensed Consolidated Balance Sheet
Noncurrent deferred income tax liabilities	(2,604)	(2,202)	(2,604)		(2,202)		(2,455)
Other long-term liabilities	11,532	10,675	11,532		10,675		11,065
Redeemable noncontrolling interests	4,458	3,648	4,458		3,648		3,965
Retained earnings	(4,249)	(3,593)	(4,249)		(3,593)		(4,006)	(3,086)
Noncontrolling interests in subsidiaries	(9,137)	(8,528)	(9,137)		(8,528)		(8,569)	(8,506)
Total stockholders' equity	(13,386)	(12,121)	(13,386)		(12,121)		(12,575)	(11,592)
Condensed Consolidated Statement of Comprehensive Income
Interest expense	774	90	392		817
Income before income taxes	(774)	(90)	(392)		(817)
Income tax expense	(294)	(34)	(149)		(310)
Net income, including noncontrolling interests	(480)	(56)	(243)		(507)
Net income, net of noncontrolling interests	(480)	(56)	(243)		(507)
Comprehensive income	(480)	(56)	(243)		(507)
Basic earnings per common share	$ (0.02)	$ (0.01)	$ (0.01)		$ (0.02)
Earnings per common share - assuming dilution	$ (0.02)		$ (0.01)		$ (0.02)
Consolidated Statement of Cash Flows
Net income, including noncontrolling interests	(480)	(56)	(243)		(507)
Deferred income taxes			(149)		(310)
Other			392		817
As Restated [Member]
Consolidated Statement of Stockholders' Equity
Retained earnings	326,071	268,110	326,071		268,110		294,801	240,066
Total stockholders' equity	212,160	211,680	212,160		211,680		205,647	195,608
Condensed Consolidated Balance Sheet
Noncurrent deferred income tax liabilities	7,044	1,283	7,044		1,283		6,692
Other long-term liabilities	39,094	23,153	39,094		23,153		36,676
Redeemable noncontrolling interests	4,458	3,648	4,458		3,648		3,965
Retained earnings	326,071	268,110	326,071		268,110		294,801	240,066
Total stockholders' equity	212,160	211,680	212,160		211,680		205,647	195,608
Condensed Consolidated Statement of Comprehensive Income
Interest expense	1,056	383	962		1,718
Income before income taxes	23,466	18,977	50,986		45,030
Income tax expense	8,005	5,980	17,218		14,935
Net income, including noncontrolling interests	15,461	12,997	33,768		30,095
Net income, net of noncontrolling interests	14,289	12,068	31,270	[1]	28,044	[1]
Comprehensive income	15,010	12,483	33,528		30,854
Basic earnings per common share	$ 0.60	$ 0.47	$ 1.31		$ 1.10
Earnings per common share - assuming dilution	$ 0.59	$ 0.47	$ 1.29		$ 1.09
Consolidated Statement of Cash Flows
Net income, including noncontrolling interests	15,461	12,997	33,768		30,095
Deferred income taxes			1,797		4,022
Other			2,872		1,133
Net cash provided by operating activities			65,162		52,925
Reclassifications [Member]
Condensed Consolidated Balance Sheet
Long-term accrued income taxes	(3,924)		(3,924)
Other long-term liabilities	$ 3,924		$ 3,924

[1] Net income at June 24, 2012 and June 26, 2011 is net of $2,498 and $2,051, respectively, allocable to the redeemable noncontrolling interests for our joint venture arrangements.