CONDENSED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 3,838	$ 11,059
Accounts receivable:
Trade - less allowance for doubtful accounts	331,424	313,182
Other	35,327	43,074
Inventories - net	164,726	177,397
Prepaid expenses and other current assets	40,542	39,248
Deferred income taxes	9,929	12,296
Total current assets	585,786	596,256
Property and equipment	3,275,602	3,219,113
Less accumulated depreciation	(930,174)	(903,948)
Property and equipment - net	2,345,428	2,315,165
Goodwill	595,234	596,030
Other assets	171,637	145,677
Total assets	3,698,085	3,653,128
Current liabilities:
Current portion of long-term debt	71,500	65,000
Income taxes payable	6,003	2,369
Accounts payable	148,658	156,763
Accrued liabilities	105,200	114,031
Deferred revenues	32,565	16,857
Total current liabilities	363,926	355,020
Long-term debt - less current portion	1,031,960	1,070,110
Deferred income taxes	446,497	426,096
Other long-term liabilities	86,262	94,848
Total long-term liabilities	1,564,719	1,591,054
Contingencies and commitments
Kirby stockholders' equity:
Common stock, $.10 par value per share. Authorized 120,000,000 shares, issued 59,776,000 shares	5,978	5,978
Additional paid-in capital	398,880	397,785
Accumulated other comprehensive income - net	(58,771)	(61,127)
Retained earnings	1,495,657	1,439,079
Treasury stock - at cost, 3,044,000 at March 31, 2013 and 3,191,000 at December 31, 2012	(84,275)	(86,747)
Total Kirby stockholders' equity	1,757,469	1,694,968
Noncontrolling interests	11,971	12,086
Total equity	1,769,440	1,707,054
Total liabilities and equity	$ 3,698,085	$ 3,653,128