Segment Reporting (Summary Of Segment Performance) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Segment Reporting Information [Line Items]
Revenue	$ 307,201	$ 300,954	$ 317,862	$ 292,672	$ 283,757	$ 269,628	$ 281,482	$ 268,525	$ 1,218,689		$ 1,103,392		$ 1,031,633
Income (loss) from operations	55,299	56,096	71,298	53,532	50,804	49,814	54,835	48,428	236,225		203,881		175,969
Interest expense, net									1,803		1,752		1,430
Income before provision for income taxes									234,422		202,129		174,539
Provision for income taxes									72,668		60,809		52,304
Net income									161,754		141,320		122,235
Net income attributable to noncontrolling interest									(32)		36		10
Net income attributable to IDEXX Laboratories, Inc. stockholders	38,010	38,507	48,657	36,612	36,371	34,694	37,193	33,026	161,786		141,284		122,225
Depreciation and amortization									48,202		45,956		49,773
Segment assets	1,030,814				897,144				1,030,814		897,144		808,527
Expenditures for long-lived assets									52,464	[1]	38,908	[1]	52,332	[1]
Companion Animal Group [Member]
Segment Reporting Information [Line Items]
Revenue									999,722		905,655		843,303
Income (loss) from operations									189,834		165,213		131,738
Depreciation and amortization									39,165		38,211		41,865
Segment assets	635,461				551,492				635,461		551,492		519,098
Expenditures for long-lived assets									42,198	[1]	31,499	[1]	41,111	[1]
Water [Member]
Segment Reporting Information [Line Items]
Revenue									82,125		76,514		73,214
Income (loss) from operations									33,844		31,613		30,843
Depreciation and amortization									1,717		1,532		1,457
Segment assets	45,479				41,884				45,479		41,884		43,893
Expenditures for long-lived assets									2,487	[1]	1,642	[1]	3,110	[1]
Livestock And Poultry Diagnostics Segment Revenue [Member]
Segment Reporting Information [Line Items]
Revenue									94,112		81,177		77,208
Income (loss) from operations									23,739		19,603		17,351
Depreciation and amortization									4,537		3,809		4,544
Segment assets	64,727				57,390				64,727		57,390		57,897
Expenditures for long-lived assets									5,699	[1]	2,815	[1]	3,337	[1]
Other [Member]
Segment Reporting Information [Line Items]
Revenue									42,730		40,046		37,908
Income (loss) from operations									2,556		4,125		3,179
Depreciation and amortization									2,783		2,404		1,907
Segment assets	44,641				38,028				44,641		38,028		35,779
Expenditures for long-lived assets									2,080	[1]	2,952	[1]	4,774	[1]
Unallocated Amounts [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations									(13,748)		(16,673)		(7,142)
Segment assets	$ 240,506				$ 208,350				$ 240,506		$ 208,350		$ 151,860

[1] Expenditures for long-lived assets exclude expenditures for intangible assets. See Note 3 for information regarding acquisitions of intangible assets during the years ended December 31, 2011, 2010 and 2009.