Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 26, 2015	Dec. 27, 2014
Allowance on trade accounts receivable	$ 4,287	$ 4,338
Allowance on other receivables	4,306	4,189
Accumulated depreciation and amortization on operating property	$ 175,310	$ 160,681
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized shares	160,000,000	160,000,000
Common stock, issued shares	67,379,568	67,268,817
Treasury stock, shares	24,193,516	22,474,331