Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 170,551	$ 164,485
Accounts receivable, net	245,836	251,206
Prepaids and other current assets	62,583	58,702
Deferred tax assets, net	5,406	14,169
Income tax receivable	15,904	14,982
Total current assets	500,280	503,544
Long-term assets
Property, plant and equipment, net	108,351	112,276
Goodwill	95,191	94,679
Contract acquisition costs, net	1,607	1,860
Deferred tax assets, net	43,086	35,429
Other long-term assets	98,980	99,385
Total long-term assets	347,215	343,629
Total assets	847,495	847,173
Current liabilities
Accounts payable	20,219	23,494
Accrued employee compensation and benefits	62,354	71,621
Other accrued expenses	26,580	29,056
Income taxes payable	12,927	12,650
Deferred tax liabilities, net	323	341
Deferred revenue	27,224	26,892
Other current liabilities	8,098	7,351
Total current liabilities	157,725	171,405
Long-term liabilities
Line of credit	115,000	108,000
Deferred tax liabilities, net	2,391	3,029
Deferred rent	8,707	8,589
Other long-term liabilities	50,064	55,813
Total long-term liabilities	176,162	175,431
Total liabilities	333,887	346,836
Commitments and contingencies (Note 10)
Stockholders' equity
Preferred stock - $0.01 par value: 10,000,000 shares authorized; zero shares outstanding as of March 31, 2013 and December 31, 2012	0	0
Common stock - $0.01 par value; 150,000,000 shares authorized; 52,200,947 and 52,288,567 shares outstanding as of March 31, 2012 and December 31, 2012, respectively	521	522
Additional paid-in capital	345,158	350,714
Treasury stock at cost: 29,851,306 and 29,763,686 shares as of March 31, 2013 and December 31, 2012, respectively	(432,866)	(428,716)
Accumulated other comprehensive income	28,547	22,981
Retained earnings	558,752	540,791
Noncontrolling interest	13,496	14,045
Total stockholders' equity	513,608	500,337
Total liabilities and stockholders' equity	$ 847,495	$ 847,173