Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 43,291	$ 27,342
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,146	6,997
Bad debt provision	5,921	21,465
Deferred income tax benefit	(3,923)	(18)
Share-based compensation expense	3,925	3,659
Amortization of premium on marketable securities	950	712
Unrealized gain on deferred compensation fund investments	(961)	(5,041)
Changes in operating assets and liabilities:
Accounts and notes receivable	2,635	(25,305)
Inventories and supplies	2,840	1,305
Prepaid expenses and other assets	(3,931)	(2,847)
Deferred compensation funding	990	89
Accounts payable and other accrued expenses	(964)	(8,824)
Accrued payroll, accrued and withheld payroll taxes	16,104	(2,678)
Income taxes payable	12,847	(7,140)
Accrued insurance claims	5,396	5,423
Deferred compensation liability	117	5,200
Net cash provided by operating activities	92,383	20,339
Cash flows from investing activities:
Disposals of fixed assets	307	87
Additions to property and equipment	(1,835)	(2,496)
Purchases of marketable securities	(6,939)	(8,234)
Sales of marketable securities	5,779	7,145
Net cash used in investing activities	(2,688)	(3,498)
Cash flows from financing activities:
Dividends paid	(30,161)	(29,276)
Reissuance of treasury stock pursuant to Dividend Reinvestment Plan	45	46
Proceeds from the exercise of stock options	1,862	3,099
Repayments of short-term borrowings	(10,000)	0
Payments of statutory withholding on net issuance of restricted stock units	(661)	(579)
Net cash used in financing activities	(38,915)	(26,710)
Net change in cash and cash equivalents	50,780	(9,869)
Cash and cash equivalents at beginning of the period	27,329	26,025
Cash and cash equivalents at end of the period	$ 78,109	$ 16,156