Condensed Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Revenues	$ 182,411	$ 173,953	$ 329,055	$ 305,277
Costs and expenses:
Operating	116,472	111,242	216,356	207,072
Selling	28,197	25,684	52,600	48,671
General and administrative	11,480	10,783	24,078	22,007
Depreciation and amortization	9,670	9,840	19,127	19,424
Gain on sale of assets, net	(678)	(163)	(884)	(244)
Total costs and expenses	165,141	157,386	311,277	296,930
Income from operations	17,270	16,567	17,778	8,347
Other income (expense):
Interest expense	(707)	(984)	(1,410)	(1,874)
Interest income	29	9	56	14
Other, net	(874)	(661)	(1,509)	(1,324)
Income before income taxes	15,718	14,931	14,915	5,163
Income taxes	6,302	5,772	6,070	2,050
Net income	$ 9,416	$ 9,159	$ 8,845	$ 3,113
Net income per share:
Basic	$ 0.68	$ 0.65	$ 0.64	$ 0.22
Diluted	$ 0.66	$ 0.63	$ 0.62	$ 0.21
Weighted-average shares outstanding:
Basic	13,838	14,058	13,851	14,093
Diluted	14,286	14,569	14,325	14,612
Dividends declared per share	$ 0.045	$ 0.043	$ 0.088	$ 0.085