Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenues	$ 1,286,340	$ 1,327,523	$ 1,263,460
Operating expenses:
Direct salaries and related costs	836,516	892,110	855,266
General and administrative	297,257	298,129	297,519
Depreciation, net	43,752	45,363	42,084
Amortization of intangibles	14,170	14,396	14,863
Net (gain) loss on disposal of property and equipment	381	(2,030)	201
Total operating expenses	1,192,076	1,247,968	1,209,933
Income from operations	94,264	79,555	53,527
Other income (expense):
Interest income	668	958	866
Interest (expense)	(2,465)	(2,011)	(2,307)
Other income (expense)	(2,484)	(1,343)	(761)
Total other income (expense)	(4,281)	(2,396)	(2,202)
Income before income taxes	89,983	77,159	51,325
Income taxes	21,386	19,368	14,065
Net income	$ 68,597	$ 57,791	$ 37,260
Net income per common share:
Basic	$ 1.64	$ 1.36	$ 0.87
Diluted	$ 1.62	$ 1.35	$ 0.87
Weighted average common shares outstanding:
Basic	41,899	42,609	42,877
Diluted	42,447	42,814	42,925