SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Accounting Policies [Line Items]
Restricted cash	$ 600	$ 400
Unbilled revenue within accounts receivable	6,700	6,600
Provision for doubtful accounts	1,089	626	855
Write-offs of doubtful accounts	900	900	1,000
Accounts receivable, allowance for doubtful accounts	800	600	900
Capitalized cost incurred to develop software features	15,300	15,300	16,400
Capitalized software depreciation expense	12,100	10,200	6,100
Asset impairments	879	456	290
Interest earned on cost method investment	8.00%
Write-off of cumulative translation adjustments, net of tax			4,676
Repurchase and retirement of common stock, shares	3,200,000	3,000,000
Repurchase and retirement of common stock, value	27,892	22,066	59,342
Average price per share paid for stock repurchase	$ 8.81	$ 7.41
Shares withheld in satisfaction of employee tax withholding obligations	246,735	208,944
Payments related to tax withholding for share-based compensation	2,000	1,800
Preferred stock, shares authorized	5,000
Preferred stock, par or stated value per share	$ 0.01
Advertising and promotion costs	8,900	16,900	10,200
Prepaid Advertising	300	0
Convertible Investment In Marketplace [Member]
Significant Accounting Policies [Line Items]
Investment accounted for under cost method investment	1,000
Investment In Conferencing Company [Member]
Significant Accounting Policies [Line Items]
Investment accounted for under cost method investment		1,000
Accumulated Other Comprehensive Income (Loss) [Member]
Significant Accounting Policies [Line Items]
Write-off of cumulative translation adjustments, net of tax			$ 4,676
Minimum [Member]
Significant Accounting Policies [Line Items]
Finite lived intangible assets useful life	1 year
Maximum [Member]
Significant Accounting Policies [Line Items]
Finite lived intangible assets useful life	20 years
Furniture and Fixtures [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Tangible assets estimated useful life	5 years
Furniture and Fixtures [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Tangible assets estimated useful life	7 years
Software [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Finite lived intangible assets useful life	2 years
Software [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Finite lived intangible assets useful life	5 years
Computer, communication and network equipment [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Tangible assets estimated useful life	3 years
Computer, communication and network equipment [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Tangible assets estimated useful life	10 years
Software Development [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Finite lived intangible assets useful life	5 years