Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 144,903	$ 164,485
Accounts receivable, net	245,080	251,206
Prepaids and other current assets	58,987	58,702
Deferred tax assets, net	8,672	14,169
Income tax receivable	9,367	14,982
Total current assets	467,009	503,544
Long-term assets
Property, plant and equipment, net	120,111	112,276
Goodwill	98,695	94,679
Contract acquisition costs, net	2,077	1,860
Deferred tax assets, net	46,720	35,429
Other long-term assets	103,757	99,385
Total long-term assets	371,360	343,629
Total assets	838,369	847,173
Current liabilities
Accounts payable	35,719	23,494
Accrued employee compensation and benefits	67,982	71,621
Other accrued expenses	26,365	29,056
Income taxes payable	4,504	12,650
Deferred tax liabilities, net	300	341
Deferred revenue	33,609	26,892
Other current liabilities	10,519	7,351
Total current liabilities	178,998	171,405
Long-term liabilities
Line of credit	118,000	108,000
Deferred tax liabilities, net	2,277	3,029
Deferred rent	9,826	8,589
Other long-term liabilities	57,897	55,813
Total long-term liabilities	188,000	175,431
Total liabilities	366,998	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 September 30, 2013 and December 31, 2012	0	0
Common stock - $0.01 par value; 150,000,000 shares authorized; 50,496,816 and 52,288,567 shares outstanding as of September 30, 2013 and December 31, 2012, respectively	504	522
Additional paid-in capital	354,501	350,714
Treasury stock at cost: 31,555,437 and 29,763,686 shares as of September 30, 2013 and December 31, 2012, respectively	(473,318)	(428,716)
Accumulated other comprehensive income (loss)	(7,886)	22,981
Retained earnings	588,710	540,791
Noncontrolling interest	8,860	14,045
Total stockholders' equity	471,371	500,337
Total liabilities and stockholders' equity	$ 838,369	$ 847,173