Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income (loss)	$ 48,890	$ 6,378
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	5,678	5,306
Bad debt provision	2,225	3,720
Deferred income tax (benefits)	20,767	(11,920)
Stock-based compensation expense	2,567	2,277
Amortization of premium on marketable securities	314	263
Unrealized loss (gain) on deferred compensation fund investments	939	(694)
Changes in operating assets and liabilities:
Accounts and notes receivable	(11,170)	(12,178)
Inventories and supplies	(425)	(361)
Prepaid expenses and other assets	(2,020)	(3,082)
Deferred compensation funding	836	(2,004)
Accounts payable and other accrued expenses	(7,703)	14,591
Accrued payroll, accrued and withheld payroll taxes	(18,189)	(11,480)
Accrued insurance claims	11,384	30,902
Deferred compensation liability	(1,415)	3,155
Income taxes payable	(173)	(1,222)
Net cash provided by operating activities	52,505	23,651
Cash flows from investing activities:
Disposals of fixed assets	248	393
Additions to property and equipment	(3,975)	(3,656)
Purchases of marketable securities	(52,219)	(3,633)
Sales of marketable securities	4,786	2,945
Net cash used in investing activities	(51,160)	(3,951)
Cash flows from financing activities:
Dividends paid	(38,338)	(36,598)
Reissuance of treasury stock pursuant to Dividend Reinvestment Plan	83	55
Tax benefit from equity compensation plans	1,062	1,042
Proceeds from the exercise of stock options	4,937	4,522
Net cash used in financing activities	(32,256)	(30,979)
Net change in cash and cash equivalents	(30,911)	(11,279)
Cash and cash equivalents at beginning of the period	75,280	64,155
Cash and cash equivalents at end of the period	44,369	52,876
Supplementary Cash Flow Information:
Cash paid for interest	137	122
Cash paid for income taxes, net of refunds	7,508	15,810
Issuance of Common Stock in 2015 and 2014, respectively, pursuant to Employee Stock Purchase Plan	$ 1,701	$ 1,851