Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash Flows from Operating Activities:
Net income	$ 237,398	$ 228,669
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation & amortization	120,040	113,134
Stock-based compensation expense	17,591	19,700
Gain on sale of assets and businesses	0	(703)
Changes in assets & liabilities, net of effects from acquisitions and dispositions:
Accounts receivable	(101,619)	(72,526)
Accrued interest	(2,687)	(6,209)
Accrued and deferred income taxes	52,291	61,674
Other working capital accounts	107,878	59,032
Other assets and deferred charges	(3,771)	(5,438)
Other	(38,298)	8,211
Accrued insurance expense, net of commercial premiums paid	24,398	23,125
Payments made in settlement of self-insurance claims	(22,320)	(18,765)
Net cash provided by operating activities	390,901	409,904
Cash Flows from Investing Activities:
Property and equipment additions, net of disposals	(169,848)	(189,041)
Acquisition of property and businesses	0	(20,931)
Inflows (outflows) from foreign exchange contracts that hedge our net U.K. investment	12,895	(45,853)
Proceeds received from sales of assets and businesses	0	839
Costs incurred for purchase and implementation of information technology applications	(9,678)	(8,570)
Decrease in capital reserves of commercial insurance subsidiary	0	100
Investment in, and advances to, joint ventures and other	(879)	(8,675)
Net cash used in investing activities	(167,510)	(272,131)
Cash Flows from Financing Activities:
Reduction of long-term debt	(114,540)	(140,676)
Additional borrowings	8,700	20,500
Repurchase of common shares	(143,785)	(9,441)
Dividends paid	(9,081)	(9,422)
Issuance of common stock	2,726	2,545
Profit distributions to noncontrolling interests	(10,314)	(4,217)
Net cash used in financing activities	(266,294)	(140,711)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	794	1,857
Decrease in cash, cash equivalents and restricted cash	(42,109)	(1,081)
Cash, cash equivalents and restricted cash, beginning of period	199,685	167,297
Cash, cash equivalents and restricted cash, end of period	157,576	166,216
Supplemental Disclosures of Cash Flow Information:
Interest paid	41,050	41,539
Income taxes paid, net of refunds	5,087	2,749
Noncash purchases of property and equipment	71,987	$ 84,708
Right-of-use assets obtained in exchange for lease obligations	$ 355,981