Stock-Based Compensation (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2012 Y	Dec. 31, 2011	Dec. 31, 2010
Stock-Based Compensation Expense
Stock-based employee compensation expense	$ 20,801,000	$ 19,138,000	$ 18,430,000
Tax effect on stock-based compensation expense	(8,087,000)	(7,472,000)	(8,160,000)
Capitalized stock-based compensation expense	198,000	233,000	94,000
Total unrecognized compensation cost	38,900,000
Weighted average period for recognition of compensation cost (in years)	2.5
Continuing operations
Stock-Based Compensation Expense
Effect on net income, net of tax	12,714,000	11,666,000	10,270,000
Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	12,344,000	10,973,000	12,080,000
Tax effect on stock-based compensation expense	(4,763,000)	(4,303,000)	(5,592,000)
Options, SARs & ESPP | Continuing operations
Stock-Based Compensation Expense
Effect on net income, net of tax	7,581,000	6,670,000	6,488,000
RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	8,457,000	8,165,000	6,350,000
Tax effect on stock-based compensation expense	(3,324,000)	(3,169,000)	(2,568,000)
RSU | Continuing operations
Stock-Based Compensation Expense
Effect on net income, net of tax	5,133,000	4,996,000	3,782,000
Total cost of revenues
Stock-Based Compensation Expense
Stock-based employee compensation expense	3,641,000	3,468,000	2,915,000
Total cost of revenues | Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	2,074,000	1,858,000	1,870,000
Total cost of revenues | RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	1,567,000	1,610,000	1,045,000
Cost of recurring revenues
Stock-Based Compensation Expense
Stock-based employee compensation expense	2,405,000	2,154,000	1,774,000
Cost of recurring revenues | Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	1,432,000	1,105,000	1,066,000
Cost of recurring revenues | RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	973,000	1,049,000	708,000
Cost of non-recurring revenues
Stock-Based Compensation Expense
Stock-based employee compensation expense	1,236,000	1,314,000	1,141,000
Cost of non-recurring revenues | Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	642,000	753,000	804,000
Cost of non-recurring revenues | RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	594,000	561,000	337,000
Total operating expenses
Stock-Based Compensation Expense
Stock-based employee compensation expense	17,160,000	15,670,000	15,515,000
Total operating expenses | Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	10,270,000	9,115,000	10,210,000
Total operating expenses | RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	6,890,000	6,555,000	5,305,000
Sales and marketing
Stock-Based Compensation Expense
Stock-based employee compensation expense	7,165,000	6,305,000	5,866,000
Sales and marketing | Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	4,881,000	4,324,000	4,141,000
Sales and marketing | RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	2,284,000	1,981,000	1,725,000
Product development
Stock-Based Compensation Expense
Stock-based employee compensation expense	5,821,000	5,138,000	5,200,000
Product development | Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	2,952,000	2,348,000	2,856,000
Product development | RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	2,869,000	2,790,000	2,344,000
General and administrative
Stock-Based Compensation Expense
Stock-based employee compensation expense	4,174,000	4,227,000	4,449,000
General and administrative | Options, SARs & ESPP
Stock-Based Compensation Expense
Stock-based employee compensation expense	2,437,000	2,443,000	3,213,000
General and administrative | RSU
Stock-Based Compensation Expense
Stock-based employee compensation expense	$ 1,737,000	$ 1,784,000	$ 1,236,000