CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net earnings	$ 63,011	$ 57,552
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	41,036	40,996
Provision for deferred income taxes	8,784	21,497
Amortization of unearned share-based compensation	2,153	2,134
Other	3,605	2,155
Decrease in cash flows resulting from changes in operating assets and liabilities, net	(3,378)	(26,538)
Net cash provided by operating activities	115,211	97,796
Cash flows from investing activities:
Capital expenditures	(62,257)	(71,157)
Acquisition of businesses and marine equipment	0	(2,111)
Proceeds from disposition of assets	363	1,861
Net cash used in investing activities	(61,894)	(71,407)
Cash flows from financing activities:
Payments on bank credit facilities, net	(41,150)	(43,650)
Borrowings on long-term debt	0	225,000
Payments on long-term debt	0	(213,000)
Proceeds from exercise of stock options	4,331	2,262
Payment of contingent liability	(4,756)	(5,000)
Excess tax benefit from equity compensation plans	4,653	1,866
Other	(1,173)	(1,088)
Net cash used in financing activities	(38,095)	(33,610)
Increase (decrease) in cash and cash equivalents	15,222	(7,221)
Cash and cash equivalents, beginning of year	4,022	11,059
Cash and cash equivalents, end of period	19,244	3,838
Cash paid (received) during the period:
Interest	8,957	5,420
Income taxes	$ 565	$ (177)