Consolidated Statements of Cash Flows (unaudited) (USD $)	3 Months Ended
	Mar. 26, 2013	Mar. 27, 2012
Cash flows from operations:
Net income	$ 48,117,000	$ 41,184,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,365,000	21,321,000
Stock-based compensation expense	2,728,000	2,402,000
Excess tax benefit from exercise of stock options	(224,000)	(1,869,000)
Deferred income taxes	11,666,000	1,426,000
Other	413,000	(1,896,000)
Changes in operating assets and liabilities, excluding the effect of acquisitions and dispositions:
Trade and other accounts receivable, net	17,597,000	22,007,000
Inventories	1,437,000	983,000
Prepaid expenses	3,022,000	2,313,000
Deposits and other	149,000	22,000
Accounts payable	2,296,000	(6,603,000)
Accrued expenses	(24,725,000)	(5,855,000)
Deferred rent	1,010,000	758,000
Other long-term liabilities	(6,418,000)	(3,809,000)
Net cash provided by operating activities	81,433,000	72,384,000
Cash flows from investing activities:
Additions to property and equipment	(36,031,000)	(30,119,000)
Acquisitions, net of cash acquired	0	(48,150,000)
Net cash used in investing activities	(36,031,000)	(78,269,000)
Cash flows from financing activities:
Repurchase of common stock	(20,304,000)	(253,000)
Exercise of employee stock options	80,000	2,470,000
Excess tax benefit from exercise of stock options	224,000	1,869,000
Proceeds from issuance of common stock under employee benefit plans	773,000	598,000
Net cash provided by (used in) financing activities	(19,227,000)	4,684,000
Net increase (decrease) in cash and cash equivalents	26,175,000	(1,201,000)
Cash and cash equivalents at beginning of period	297,141,000	222,640,000
Cash and cash equivalents at end of period	$ 323,316,000	$ 221,439,000