CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net earnings	$ 79,078	$ 313,903	$ 142,804
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	224,972	202,881	200,917
Provision (credit) for doubtful accounts	1,289	224	(467)
Provision (benefit) for deferred income taxes	34,881	(256,263)	51,296
Loss (gain) on disposition of assets	(1,968)	4,487	127
Equity in earnings of affiliates, net of distributions and contributions	(355)	732	(532)
Impairment of long-lived assets	82,705	105,712	0
Impairment of goodwill	2,702	0	0
Amortization of unearned share-based compensation	19,104	11,460	11,675
Amortization of major maintenance costs	20,760	21,207	19,869
Amortization of debt issuance costs	1,218	986	801
Increase (decrease) in cash flows resulting from changes in:
Accounts receivable	12,511	(60,405)	(12,750)
Inventory	(144,685)	19,673	3,182
Other assets	(38,090)	(17,049)	(30,853)
Income taxes payable	(457)	(11,823)	15,413
Accounts payable	22,622	20,758	(1,739)
Accrued and other liabilities	30,712	(3,105)	16,051
Net cash provided by operating activities	346,999	353,378	415,794
Cash flows from investing activities:
Capital expenditures	(301,861)	(177,222)	(231,066)
Acquisitions of businesses and marine equipment, net of cash acquired	(533,897)	(470,101)	(137,072)
Proceeds from disposition of assets	53,392	54,229	18,617
Other	(250)	0	0
Net cash used in investing activities	(782,616)	(593,094)	(349,521)
Cash flows from financing activities:
Borrowings (payments) on bank credit facilities, net	(78,455)	269,859	(52,848)
Borrowings (payments) on long-term debt	499,295	(13,721)	0
Payment of debt issue costs	(4,276)	(1,243)	0
Return of investment to noncontrolling interests	(915)	(862)	(1,976)
Proceeds from exercise of stock options	13,264	3,039	321
Purchase of treasury stock	(776)	0	(1,827)
Payments related to tax withholding for share-based compensation	(4,822)	(2,881)	(1,756)
Acquisitions of noncontrolling interest	0	(7)	(8,438)
Net cash provided by (used in) financing activities	423,315	254,184	(66,524)
Increase (decrease) in cash and cash equivalents	(12,302)	14,468	(251)
Cash and cash equivalents, beginning of year	20,102	5,634	5,885
Cash and cash equivalents, end of year	7,800	20,102	5,634
Cash paid during the period:
Interest paid	40,772	21,663	19,878
Income taxes paid	640	27,196	18,162
Capital expenditures included in accounts payable	(16,441)	5,525	(2,037)
Non-cash investing activity:
Fair value of property transferred in acquisition	0	0	3,681
Stock issued in acquisition	0	366,554	0
Cash acquired in acquisition	2,313	98	0
Debt assumed in acquisition	$ 0	$ 13,724	$ 0