Condensed Consolidated Statements of Income and Comprehensive Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Apr. 02, 2011
Condensed Financial Statements, Captions [Line Items]
Net sales	$ 858,177	$ 790,273
Cost of goods sold	577,458	541,214
Gross profit	280,719	249,059
Selling, general and administrative	175,010	144,760
Research and development	20,757	18,122
Operating (loss) income	84,952	86,177
Other (income) expense:
Equity (income) losses of unconsolidated subsidiaries	(1,049)	(235)
Net interest (income) expense	14,768	9,325
Income (loss) before income taxes and noncontrolling interest	71,233	77,087
Provision for income taxes	9,079	25,053
Net income before noncontrolling interest	62,154	52,034
Noncontrolling interest	1,340	1,493
Net income attributable to Pentair, Inc.	60,814	50,541
Comprehensive income (loss)	104,238	94,813
Parent Company
Condensed Financial Statements, Captions [Line Items]
Selling, general and administrative	16,884	6,606
Research and development	223	170
Operating (loss) income	(17,107)	(6,776)
Earnings from investment in subsidiaries	(53,393)	(37,306)
Other (income) expense:
Equity (income) losses of unconsolidated subsidiaries		(176)
Net interest (income) expense	(29,034)	(27,379)
Income (loss) before income taxes and noncontrolling interest	65,320	58,085
Provision for income taxes	4,506	7,544
Net income before noncontrolling interest	60,814	50,541
Net income attributable to Pentair, Inc.	60,814	50,541
Comprehensive income (loss)	101,995	91,408
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	558,068	515,054
Cost of goods sold	386,058	355,561
Gross profit	172,010	159,493
Selling, general and administrative	88,363	85,119
Research and development	10,610	10,846
Operating (loss) income	73,037	63,528
Earnings from investment in subsidiaries	(798)
Other (income) expense:
Equity (income) losses of unconsolidated subsidiaries	(908)
Net interest (income) expense	38,183	38,485
Income (loss) before income taxes and noncontrolling interest	36,560	25,043
Provision for income taxes	307	8,481
Net income before noncontrolling interest	36,253	16,562
Net income attributable to Pentair, Inc.	36,253	16,562
Comprehensive income (loss)	67,292	21,772
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net sales	386,177	341,578
Cost of goods sold	277,162	251,730
Gross profit	109,015	89,848
Selling, general and administrative	70,069	53,317
Research and development	9,924	7,106
Operating (loss) income	29,022	29,425
Earnings from investment in subsidiaries	(964)
Other (income) expense:
Equity (income) losses of unconsolidated subsidiaries	(141)	(59)
Net interest (income) expense	5,619	(1,781)
Income (loss) before income taxes and noncontrolling interest	24,508	31,265
Provision for income taxes	4,266	9,028
Net income before noncontrolling interest	20,242	22,237
Noncontrolling interest	1,340	1,493
Net income attributable to Pentair, Inc.	18,902	20,744
Comprehensive income (loss)	27,728	38,017
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net sales	(86,068)	(66,359)
Cost of goods sold	(85,762)	(66,077)
Gross profit	(306)	(282)
Selling, general and administrative	(306)	(282)
Earnings from investment in subsidiaries	55,155	37,306
Other (income) expense:
Income (loss) before income taxes and noncontrolling interest	(55,155)	(37,306)
Net income before noncontrolling interest	(55,155)	(37,306)
Net income attributable to Pentair, Inc.	(55,155)	(37,306)
Comprehensive income (loss)	$ (92,777)	$ (56,384)