Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income (loss)	$ 6,378	$ 41,677
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	5,306	4,491
Bad debt provision	3,720	940
Deferred income benefits	(11,920)	(2,312)
Stock-based compensation expense	2,277	1,791
Amortization of premium on marketable securities	263	449
Unrealized gains on deferred compensation fund investments	(694)	(1,711)
Changes in operating assets and liabilities:
Accounts and notes receivable	(12,178)	(46,119)
Inventories and supplies	(361)	(1,904)
Prepaid expenses and other assets	(3,082)	171
Deferred compensation funding	(2,004)	(3,408)
Accounts payable and other accrued expenses	14,591	13,866
Accrued payroll, accrued and withheld payroll taxes	(11,480)	(11,945)
Accrued insurance claims	30,902	2,011
Deferred compensation liability	3,155	5,510
Income taxes payable	(1,222)	4,365
Net cash provided by operating activities	23,651	7,872
Cash flows from investing activities:
Disposals of fixed assets	393	158
Additions to property and equipment	(3,656)	(2,735)
Purchases of marketable securities	(3,633)	(4,799)
Sales of marketable securities	2,945	13,970
Cash paid for acquisition	0	(5,000)
Net cash (used in) provided by investing activities	(3,951)	1,594
Cash flows from financing activities:
Dividends paid	(36,598)	(34,760)
Reissuance of treasury stock pursuant to Dividend Reinvestment Plan	55	80
Tax benefit from equity compensation plans	1,042	1,355
Proceeds from the exercise of stock options	4,522	5,469
Net cash used in financing activities	(30,979)	(27,856)
Net change in cash and cash equivalents	(11,279)	(18,390)
Cash and cash equivalents at beginning of the period	64,155	68,949
Cash and cash equivalents at end of the period	52,876	50,559
Supplementary Cash Flow Information:
Cash paid for interest	122	0
Cash paid for income taxes, net of refunds	15,810	14,923
Issuance of Common Stock in 2014 and 2013, respectively, pursuant to Employee Stock Purchase Plan	$ 1,851	$ 1,842