Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 8,449	$ 8,291
Accounts receivable, net	267,841	261,755
Prepaid expenses and other current assets	32,921	29,762
Total current assets	309,211	299,808
Non-current assets:
Property and equipment, net	89,169	82,953
Intangible assets, net	21,053	28,727
Goodwill	637,287	625,027
Other assets	23,544	18,282
Total assets	1,080,264	1,054,797
Current liabilities:
Accounts payable	12,398	11,871
Accrued liabilities	13,895	16,144
Accrued compensation-related costs	96,773	106,779
Income tax payable	4,720	1,564
Other current liabilities	38,895	38,616
Total current liabilities	166,681	174,974
Non-current liabilities:
Deferred income tax liabilities	61,131	77,737
Other non-current liabilities	32,174	32,579
Bank debt non-current	132,944	135,030
Total non-current liabilities	226,249	245,346
Total liabilities	392,930	420,320
Stockholders' equity:
Common stock, $0.001 par value per share; 150,000 shares authorized; 58,047 and 57,325 shares issued as of December 31, 2017 and 2016, respectively	58	57
Additional paid-in capital	659,825	644,519
Treasury stock, 12,661 and 10,339 shares as of December 31, 2017 and 2016, respectively	(224,366)	(181,361)
Retained earnings	270,995	196,468
Accumulated other comprehensive loss	(19,178)	(25,206)
Total stockholders' equity	687,334	634,477
Total liabilities and stockholders' equity	$ 1,080,264	$ 1,054,797