INVESTMENT IN JOINT VENTURE - Summary of financial information for Internap Japan - (Details 1) (Internap Japan, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Internap Japan
Schedule of Equity Method Investments [Line Items]
Current assets	$ 5,192	$ 6,462	$ 5,372
Long-term assets	1,819	712	658
Current liabilities	1,406	1,355	1,288
Long-term liabilities	24	26
Net sales	10,536	11,636	10,357
Operating income	651	850	836
Net income	$ 372	$ 787	$ 813