Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets
Cash and cash equivalents	$ 164,485	$ 156,371
Accounts receivable, net	251,206	243,636
Prepaids and other current assets	58,702	37,434
Deferred tax assets, net	14,169	22,994
Income tax receivable	14,982	17,847
Total current assets	503,544	478,282
Long-term assets
Property, plant and equipment, net	112,276	100,321
Goodwill	94,679	70,844
Contract acquisition costs, net	1,860	2,866
Deferred tax assets, net	35,429	32,512
Other long-term assets	99,385	62,153
Total long-term assets	343,629	268,696
Total assets	847,173	746,978
Current liabilities
Accounts payable	23,494	27,555
Accrued employee compensation and benefits	71,621	71,500
Other accrued expenses	29,056	33,816
Income tax payable	12,650	10,051
Deferred tax liabilities, net	341	912
Deferred revenue	26,892	15,895
Other current liabilities	7,351	10,282
Total current liabilities	171,405	170,011
Long-term liabilities
Line of credit	108,000	64,000
Deferred tax liabilities, net	3,029	3,020
Deferred rent	8,589	6,729
Other long-term liabilities	55,813	32,971
Total long-term liabilities	175,431	106,720
Total liabilities	346,836	276,731
Commitments and contingencies (Note 15)
Stockholders' equity
Preferred stock - $0.01 par value: 10,000,000 shares authorized; zero shares outstanding as of December 31, 2012 and December 31, 2011	0	0
Common stock - $0.01 par value; 150,000,000 shares authorized; 52,288,567 and 56,635,319 shares outstanding as of December 31, 2012 and December 31, 2011, respectively	522	566
Additional paid-in capital	350,714	350,386
Treasury stock at cost: 29,763,686 and 25,416,934 shares as of December 31, 2012 and December 31, 2011, respectively	(428,716)	(357,267)
Accumulated other comprehensive income (loss)	22,981	(5,474)
Retained earnings	540,791	470,776
Noncontrolling interest	14,045	11,260
Total stockholders' equity	500,337	470,247
Total liabilities and stockholders' equity	$ 847,173	$ 746,978