CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net earnings	$ 191,040,000	$ 154,045,000
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	122,907,000	107,400,000
Provision for deferred income taxes	68,523,000	59,665,000
Amortization of unearned share-based compensation	8,921,000	7,331,000
Other	5,656,000	2,784,000
Decrease in cash flows resulting from changes in operating assets and liabilities, net	53,668,000	(84,997,000)
Net cash provided by operating activities	450,715,000	246,228,000
Cash flows from investing activities:
Capital expenditures	(207,047,000)	(255,887,000)
Acquisition of businesses and marine equipment	(3,643,000)	0
Proceeds from disposition of assets	30,390,000	15,165,000
Net cash used in investing activities	(180,300,000)	(240,722,000)
Cash flows from financing activities:
Payments on bank credit facilities, net	(143,180,000)	5,970,000
Borrowings on long-term debt	225,000,000	0
Payments on long-term debt	(356,000,000)	(26,005,000)
Proceeds from exercise of stock options	4,328,000	3,173,000
Payment of contingent liability	(5,000,000)	0
Excess tax benefit from equity compensation plans	2,824,000	2,342,000
Other	(2,964,000)	(2,092,000)
Net cash used in financing activities	(274,992,000)	(16,612,000)
Decrease in cash and cash equivalents	(4,577,000)	(11,106,000)
Cash and cash equivalents, beginning of year	11,059,000	16,249,000
Cash and cash equivalents, end of period	6,482,000	5,143,000
Cash paid during the period:
Interest	19,921,000	15,928,000
Income taxes	$ 23,000,000	$ 29,353,000