Consolidated Statements Of Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013
Income Statement [Abstract]
Revenues	$ 320,099	$ 298,549	$ 951,559		$ 846,057
Operating costs and expenses:
Costs of services provided	315,757	255,964	858,943		725,757
Selling, general and administrative	39,375	22,576	83,661		62,729
Other income (expense):
Investment and interest	(50)	1,184	1,134		2,437
Income (loss) before income taxes	(35,083)	21,193	10,089		60,008
Income tax provision (benefit)	(12,901)	7,403	3,711		18,331
Net income (loss)	(22,182)	13,790	6,378		41,677
Per share data:
Basic earnings (loss) per common share (dollars per share)	$ (0.31)	$ 0.20	$ 0.09		$ 0.60
Diluted earnings (loss) per common share (dollars per share)	$ (0.31)	$ 0.20	$ 0.09		$ 0.60
Weighted average number of common shares outstanding:
Basic (shares)	70,671	69,706	70,479		68,926
Diluted (shares)	70,671	70,531	71,213		69,758
Comprehensive income:
Net income (loss)	(22,182)	13,790	6,378		41,677
Other comprehensive income (loss):
Unrealized gain/(loss) on available for sale marketable securities, net of taxes	(4)	(1)	3	[1]	(84)
Total comprehensive income (loss)	$ (22,186)	$ 13,789	$ 6,381		$ 41,593

[1] All amounts are net of tax.