CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Oct. 31, 2015	Jan. 31, 2015
CONSOLIDATED BALANCE SHEETS
Accounts receivable, allowance for uncollectible accounts	$ 1,887	$ 1,604
Property and equipment, accumulated depreciation	$ 1,287,150	$ 1,251,797
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized shares	500,000,000	500,000,000
Common stock, issued shares	68,557,041	68,557,041
Treasury stock, shares	14,453,129	14,988,205