Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended	10 Months Ended				12 Months Ended
	Jan. 05, 2018	Jan. 03, 2018	Mar. 31, 2018	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Feb. 22, 2018	Jan. 19, 2018	Dec. 22, 2017	Feb. 23, 2017	Mar. 31, 2016	Jun. 23, 2015
Subsequent Event [Line Items]
Stock Repurchase Program, Authorized Amount														$ 50,000
Business Combination, Acquisition Related Costs								$ 7,000
Debt Instrument, Face Amount	$ 650,000															$ 725,000
Line of Credit Facility, Maximum Borrowing Capacity	$ 500,000															500,000
Repayments of Long-term Debt								29,063	$ 79,119	$ 62,998
Senior Notes													$ 300,000
Restructuring Percent Facility Close											20.00%
Restructuring Percent Severance Close											80.00%
Restructuring Percent Cash											95.00%
Subsequent Event [Member]
Subsequent Event [Line Items]
Business Acquisition, Name of Acquired Entity	SSNI
Business Acquisition, Share Price	$ 16.25
Business Combination, Consideration Transferred	$ 810,000
Debt Instrument, Face Amount	650,000
Line of Credit Facility, Maximum Borrowing Capacity	500,000
Senior Notes												$ 100,000
Standby Letters of Credit [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	300,000							250,000							$ 300,000
Standby Letters of Credit [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	300,000
Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	50,000							$ 50,000
Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 50,000
Secured Debt [Member]
Subsequent Event [Line Items]
Debt Instrument, Collateral								All obligations under the 2015 credit facility are guaranteed by Itron, Inc. and material U.S. domestic subsidiaries and are secured by a pledge of substantially all of the assets of Itron, Inc. and material U.S. domestic subsidiaries, including a pledge of 100% of the capital stock of material U.S. domestic subsidiaries and up to 66% of the voting stock (100% of the non-voting stock) of their first-tier foreign subsidiaries. In addition, the obligations of any foreign subsidiary who is a foreign borrower, as defined by the 2015 credit facility, are guaranteed by the foreign subsidiary and by its direct and indirect foreign parents.
Repayments of Long-term Debt								$ 29,063	79,119	62,998
Secured Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Collateral		All obligations under the 2018 credit facility are guaranteed by Itron, Inc. and material U.S. domestic subsidiaries and are secured by a pledge of substantially all of the assets of Itron, Inc. and material U.S. domestic subsidiaries, including a pledge of 100% of the capital stock of material U.S. domestic subsidiaries and up to 66% of the voting stock (100% of the non-voting stock) of their first-tier foreign subsidiaries. In addition, the obligations of any foreign subsidiary who is a foreign borrower, as defined by the 2018 credit facility, are guaranteed by the foreign subsidiary and by its direct and indirect foreign parents.
USD Denominated Term Loan [Member]
Subsequent Event [Line Items]
Debt Instrument, Face Amount																$ 225,000
Repayments of Long-term Debt								$ 14,063	11,250	$ 13,125
USD Denominated Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Repayments of Long-term Debt				$ 16,300	$ 12,200	$ 8,100	$ 4,100
Senior Notes [Member]
Subsequent Event [Line Items]
Debt Instrument, Collateral								The Notes will be jointly and severally guaranteed by each of our subsidiaries that guarantees obligations under our senior credit facilities. The Notes were not guaranteed until the release of the escrow, but once released, the Notes were fully and unconditionally guaranteed, jointly and severally, on a senior unsecured basis by each of our subsidiaries that guarantee the senior credit facilities.
Senior Notes								$ 300,000	$ 0
Debt Instrument, Interest Rate, Stated Percentage								5.00%
Minimum [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage								0.18%
Restructuring and Related Cost, Expected Cost											$ 100,000
Minimum [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.18%
Maximum [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage								0.30%
Restructuring and Related Cost, Expected Cost											$ 110,000
Maximum [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage		0.35%
London Interbank Offered Rate (LIBOR) [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis								the LIBOR rate
Debt Instrument, Basis Spread on Variable Rate								1.25%	1.25%
Debt Instrument, Interest Rate, Effective Percentage								2.82%	2.02%
London Interbank Offered Rate (LIBOR) [Member] | 2018 Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis			the LIBOR rate
Debt Instrument, Basis Spread on Variable Rate								2.00%
Debt Instrument, Interest Rate, Effective Percentage	3.56%
EURIBOR [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis								EURIBOR rate
Debt Instrument, Basis Spread on Variable Rate								1.25%	1.25%
Debt Instrument, Interest Rate, Effective Percentage								1.25%	1.25%
EURIBOR [Member] | 2018 Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis			EURIBOR
Debt Instrument, Basis Spread on Variable Rate			2.00%
Debt Instrument, Interest Rate, Effective Percentage	2.00%
Alternate base rate (3) [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis								one month LIBOR
Debt Instrument, Basis Spread on Variable Rate								1.00%
Alternate base rate (3) [Member] | 2018 Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis			one month LIBOR
Debt Instrument, Basis Spread on Variable Rate			1.00%
Alternate base rate (3) [Member] | Minimum [Member] | 2018 Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate			0.00%
Alternate base rate (1) [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis								the prime rate
Alternate base rate (1) [Member] | 2018 Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis			the prime rate
Alternate base rate (2) [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis								the Federal Reserve effective rate
Debt Instrument, Basis Spread on Variable Rate								0.50%
Alternate base rate (2) [Member] | 2018 Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Description of Variable Rate Basis			the Federal Reserve effective rate