Condensed Consolidated Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Apr. 02, 2011	Dec. 31, 2010
Current assets
Cash and cash equivalents	$ 55,438	$ 50,077	$ 57,134	$ 46,056
Accounts and notes receivable, net	680,260	569,204	625,856
Inventories	475,403	449,863	411,767
Deferred tax assets	62,405	60,899	56,370
Prepaid expenses and other current assets	115,701	107,792	57,950
Total current assets	1,389,207	1,237,835	1,209,077
Property, plant and equipment, net	393,335	387,525	338,610
Other assets
Goodwill	2,297,175	2,273,918	2,097,428	2,066,044
Intangibles, net	594,929	592,285	461,244
Other	103,560	94,750	56,328
Total other assets	2,995,664	2,960,953	2,615,000
Total assets	4,778,206	4,586,313	4,162,687
Current liabilities
Short-term borrowings	19,190	3,694	6,093
Current maturities of long-term debt	1,207	1,168	13
Accounts payable	293,398	294,858	256,492
Employee compensation and benefits	86,774	109,361	84,043
Current pension and post-retirement benefits	9,052	9,052	8,733
Accrued product claims and warranties	42,684	42,630	43,418
Income taxes	25,153	14,547	20,492
Accrued rebates and sales incentives	31,730	37,009	29,546
Other current liabilities	150,135	129,522	97,531
Total current liabilities	659,323	641,841	546,361
Other liabilities
Long-term debt	1,395,093	1,304,225	802,321
Pension and other retirement compensation	251,551	248,615	216,592
Post-retirement medical and other benefits	30,918	31,774	29,459
Long-term income taxes payable	13,382	26,470	23,548
Deferred tax liabilities	194,469	188,957	175,877
Other non-current liabilities	89,863	97,039	86,085
Total liabilities	2,634,599	2,538,921	1,880,243
Shareholders' equity attributable to Pentair, Inc.	2,027,301	1,933,329	2,167,160
Noncontrolling interest	116,306	114,063	115,284
Total shareholders' equity	2,143,607	2,047,392	2,282,444	2,205,032
Total liabilities and shareholders' equity	4,778,206	4,586,313	4,162,687
Parent Company
Current assets
Cash and cash equivalents	3,730	3,097	4,685	3,201
Accounts and notes receivable, net	5,603	828	920
Deferred tax assets	133,616	134,240	113,937
Prepaid expenses and other current assets	36,289	28,937	12,344
Total current assets	179,238	167,102	131,886
Property, plant and equipment, net	18,933	19,693	20,002
Other assets
Investments in/advances to subsidiaries	2,912,488	2,910,927	2,376,211
Other	68,237	63,508	55,588
Total other assets	2,980,725	2,974,435	2,431,799
Total assets	3,178,896	3,161,230	2,583,687
Current liabilities
Current maturities of long-term debt	2,665	2,585	118,836
Accounts payable	5,049	5,036	9,445
Employee compensation and benefits	12,470	24,466	24,218
Current pension and post-retirement benefits	9,052	9,052	8,733
Accrued product claims and warranties	165	165	12,248
Income taxes	23,536	40,999	2,318
Other current liabilities	45,408	25,050	15,551
Total current liabilities	98,345	107,353	191,349
Other liabilities
Long-term debt	1,414,113	1,312,053	802,300
Pension and other retirement compensation	185,334	182,556	138,135
Post-retirement medical and other benefits	17,677	17,024	18,135
Long-term income taxes payable	13,382	26,470	23,548
Deferred tax liabilities			25
Due to/ (from) affiliates	(634,296)	(479,943)	(802,224)
Other non-current liabilities	57,040	62,388	45,259
Total liabilities	1,151,595	1,227,901	416,527
Shareholders' equity attributable to Pentair, Inc.	2,027,301	1,933,329	2,167,160
Total shareholders' equity	2,027,301	1,933,329	2,167,160
Total liabilities and shareholders' equity	3,178,896	3,161,230	2,583,687
Guarantor Subsidiaries
Current assets
Cash and cash equivalents	10,857	3,332	3,002	3,404
Accounts and notes receivable, net	448,706	360,027	396,800
Inventories	246,245	227,472	199,662
Deferred tax assets	40,698	40,698	40,064
Prepaid expenses and other current assets	18,431	(6,886)	7,471
Total current assets	764,937	624,643	646,999
Property, plant and equipment, net	132,185	136,102	112,276
Other assets
Investments in/advances to subsidiaries	1,490,430	1,447,522	92,230
Goodwill	1,330,265	1,330,265	1,471,582
Intangibles, net	247,111	250,792	220,344
Other	7,839	27,337	4,167
Total other assets	3,075,645	3,055,916	1,788,323
Total assets	3,972,767	3,816,661	2,547,598
Current liabilities
Current maturities of long-term debt			(13)
Accounts payable	190,209	189,355	148,024
Employee compensation and benefits	17,052	30,015	19,759
Accrued product claims and warranties	22,305	22,037	22,121
Income taxes	(3,779)	(28,717)	7,524
Accrued rebates and sales incentives	23,201	25,612	21,560
Other current liabilities	56,153	53,960	31,461
Total current liabilities	305,141	292,262	250,436
Other liabilities
Long-term debt	2,417,922	2,417,922	1,947,379
Pension and other retirement compensation	(9,824)	(7,701)	501
Post-retirement medical and other benefits	32,381	33,890	36,373
Deferred tax liabilities	229,962	229,962	213,385
Due to/ (from) affiliates	870,956	751,145	(160,911)
Other non-current liabilities	1,415	1,508	1,797
Total liabilities	3,847,953	3,718,988	2,288,960
Shareholders' equity attributable to Pentair, Inc.	124,814	97,673	258,638
Total shareholders' equity	124,814	97,673	258,638
Total liabilities and shareholders' equity	3,972,767	3,816,661	2,547,598
Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	40,851	43,648	49,447	39,451
Accounts and notes receivable, net	294,942	263,201	296,182
Inventories	229,158	222,391	212,105
Deferred tax assets	13,419	13,382	9,032
Prepaid expenses and other current assets	96,744	107,121	52,328
Total current assets	675,114	649,743	619,094
Property, plant and equipment, net	242,217	231,730	206,332
Other assets
Investments in/advances to subsidiaries	90,716	92,396	785,383
Goodwill	966,910	943,653	625,846
Intangibles, net	347,818	341,493	240,900
Other	46,624	23,045	21,622
Total other assets	1,452,068	1,400,587	1,673,751
Total assets	2,369,399	2,282,060	2,499,177
Current liabilities
Short-term borrowings	19,190	3,694	6,093
Current maturities of long-term debt	1,207	1,168	29,684
Accounts payable	167,461	152,065	167,071
Employee compensation and benefits	57,252	54,880	40,066
Accrued product claims and warranties	20,214	20,428	9,049
Income taxes	5,396	2,265	10,650
Accrued rebates and sales incentives	8,529	11,397	7,986
Other current liabilities	84,343	71,890	64,710
Total current liabilities	363,592	317,787	335,309
Other liabilities
Long-term debt	543,760	542,411	399,205
Pension and other retirement compensation	76,041	73,760	77,956
Deferred tax liabilities	89,835	86,416	69,130
Due to/ (from) affiliates	613,215	711,705	948,590
Other non-current liabilities	31,408	33,143	39,029
Total liabilities	1,717,851	1,765,222	1,869,219
Shareholders' equity attributable to Pentair, Inc.	535,242	402,775	514,674
Noncontrolling interest	116,306	114,063	115,284
Total shareholders' equity	651,548	516,838	629,958
Total liabilities and shareholders' equity	2,369,399	2,282,060	2,499,177
Eliminations
Current assets
Accounts and notes receivable, net	(68,991)	(54,852)	(68,046)
Deferred tax assets	(125,328)	(127,421)	(106,663)
Prepaid expenses and other current assets	(35,763)	(21,380)	(14,193)
Total current assets	(230,082)	(203,653)	(188,902)
Other assets
Investments in/advances to subsidiaries	(4,493,634)	(4,450,845)	(3,253,824)
Other	(19,140)	(19,140)	(25,049)
Total other assets	(4,512,774)	(4,469,985)	(3,278,873)
Total assets	(4,742,856)	(4,673,638)	(3,467,775)
Current liabilities
Current maturities of long-term debt	(2,665)	(2,585)	(148,494)
Accounts payable	(69,321)	(51,598)	(68,048)
Other current liabilities	(35,769)	(21,378)	(14,191)
Total current liabilities	(107,755)	(75,561)	(230,733)
Other liabilities
Long-term debt	(2,980,702)	(2,968,161)	(2,346,563)
Post-retirement medical and other benefits	(19,140)	(19,140)	(25,049)
Deferred tax liabilities	(125,328)	(127,421)	(106,663)
Due to/ (from) affiliates	(849,875)	(982,907)	14,545
Total liabilities	(4,082,800)	(4,173,190)	(2,694,463)
Shareholders' equity attributable to Pentair, Inc.	(660,056)	(500,448)	(773,312)
Total shareholders' equity	(660,056)	(500,448)	(773,312)
Total liabilities and shareholders' equity	$ (4,742,856)	$ (4,673,638)	$ (3,467,775)