CONDENSED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net earnings	$ 91,897	$ 61,459
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	110,316	109,710
Provision for deferred income taxes	26,007	23,381
Amortization of unearned share-based compensation	7,907	13,551
Amortization of leases	(154)	0
Amortization of major maintenance costs	10,431	10,338
Amortization of debt issuance costs	719	578
Other	(5,806)	(1,778)
Decrease in cash flows resulting from changes in operating assets and liabilities, net	(53,120)	(63,484)
Net cash provided by operating activities	188,197	153,755
Cash flows from investing activities:
Capital expenditures	(127,268)	(152,911)
Acquisitions of businesses and marine equipment, net of cash acquired	(252,840)	(499,227)
Proceeds from disposition of assets	23,364	25,208
Net cash used in investing activities	(356,744)	(626,930)
Cash flows from financing activities:
Payments on bank credit facilities	(313,805)	(45,485)
Borrowings on long-term debt	500,000	499,295
Payments of debt issue costs	(2,397)	(4,263)
Proceeds from exercise of stock options	1,903	12,987
Payments related to tax withholding for share-based compensation	(2,023)	(4,813)
Other	(410)	(450)
Net cash provided by financing activities	183,268	457,271
Increase (decrease) in cash and cash equivalents	14,721	(15,904)
Cash and cash equivalents, beginning of year	7,800	20,102
Cash and cash equivalents, end of period	22,521	4,198
Cash paid (received) during the period:
Interest paid	29,271	14,085
Income taxes paid (refunded)	2,392	(132)
Operating cash outflow from operating leases	19,786	0
Non-cash investing activity:
Capital expenditures included in accounts payable	5,377	(16,498)
Cash acquired in acquisition	0	2,313
Right-of-use assets obtained in exchange for lease obligations	$ 2,537	$ 0