Business Acquisitions (Net Assets Acquired) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Business Acquisition [Line Items]
Goodwill	$ 326,748	$ 259,218	$ 180,602
BSI, TAIMMA, FINTECHNIX, PLANETSOFT, TRISYSTEMS [Member]
Business Acquisition [Line Items]
Current assets	6,262
Property and equipment	1,328
Intangible assets	20,246
Deferred tax asset, (net)	0
Other assets	202
Goodwill	67,376
Total assets acquired	95,414
Less: liabilities assumed	(34,302)
Net assets acquired	61,112
ADAM AND HCS [Member]
Business Acquisition [Line Items]
Current assets		9,710
Property and equipment		1,626
Intangible assets		20,970
Deferred tax asset, (net)		9,294
Other assets		0
Goodwill		80,516
Total assets acquired		122,116
Less: liabilities assumed		(15,696)
Net assets acquired		$ 106,420