Consolidated Statements of Equity Statement - USD ($) $ in Thousands	Total	Common Stock [Member]	Common Stock Including Additional Paid in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Parent [Member]	Noncontrolling Interest [Member]	SIlver Spring Networks, Inc. [Member] Common Stock Including Additional Paid in Capital [Member]	SIlver Spring Networks, Inc. [Member] Parent [Member]
Beginning balance (in shares) at Dec. 31, 2017		38,771,000
Beginning balance at Dec. 31, 2017	$ 805,632		$ 1,294,767	$ (170,478)	$ (337,873)	$ 786,416	$ 19,216
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(145,270)				(145,666)	(145,666)	396
Other Comprehensive Income (Loss), Net of Tax	17,883			17,883		17,883
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(981)						(981)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		62,000
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	2,883		2,883			2,883
Stock Issued During Period, Shares, Restricted Stock Award, Gross		338,000
Stock Issued During Period, Value, Restricted Stock Award, Gross	0		0			0
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture		2,000
Shares Issued, Value, Share-based Payment Arrangement, before Forfeiture	207		207			207
Stock Issued During Period, Shares, Employee Stock Purchase Plans		8,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	501		501			501
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	7,888		7,888			7,888
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(7)		(7)			(7)
Adjustments to Additional Paid in Capital, Other								$ 4,140	$ 4,140
Ending balance (in shares) at Mar. 31, 2018		39,181,000
Ending balance at Mar. 31, 2018	704,603		1,310,379	(152,595)	(471,812)	685,972	18,631
Net Income (Loss) Attributable to Parent	(123,127)
Beginning balance (in shares) at Dec. 31, 2017		38,771,000
Beginning balance at Dec. 31, 2017	805,632		1,294,767	(170,478)	(337,873)	786,416	19,216
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(121,710)
Other Comprehensive Income (Loss), Net of Tax	(14,768)
Ending balance (in shares) at Sep. 30, 2018		39,400,000
Ending balance at Sep. 30, 2018	712,332		1,326,719	(185,246)	(449,273)	692,200	20,132
Net income (loss) attributable to noncontrolling interests	1,417
Net Income (Loss) Attributable to Parent					2,657
Beginning balance (in shares) at Mar. 31, 2018		39,181,000
Beginning balance at Mar. 31, 2018	704,603		1,310,379	(152,595)	(471,812)	685,972	18,631
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	3,773					2,657
Other Comprehensive Income (Loss), Net of Tax	(33,273)			(33,273)		(33,273)
Contribution from noncontrolling interests	481						481
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		26,000
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	655		655			655
Stock Issued During Period, Shares, Restricted Stock Award, Gross		60,000
Stock Issued During Period, Value, Restricted Stock Award, Gross	0		0			0
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture		2,000
Shares Issued, Value, Share-based Payment Arrangement, before Forfeiture	207		207			207
Stock Issued During Period, Shares, Employee Stock Purchase Plans		10,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	627		627			627
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	8,317		8,317			8,317
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(16)		16			(16)
Adjustments to Additional Paid in Capital, Other								(2,388)	$ (2,388)
Ending balance (in shares) at Jun. 30, 2018		39,279,000
Ending balance at Jun. 30, 2018	682,986		1,317,781	(185,868)	(469,155)	662,758	20,228
Net income (loss) attributable to noncontrolling interests							1,116
Net Income (Loss) Attributable to Parent	19,882				19,882
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	19,787					19,882
Other Comprehensive Income (Loss), Net of Tax	622			622		622
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(1)						1
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		63,000
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	2,364		2,364			2,364
Stock Issued During Period, Shares, Restricted Stock Award, Gross		38,000
Stock Issued During Period, Value, Restricted Stock Award, Gross	0		0			0
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture		3,000
Shares Issued, Value, Share-based Payment Arrangement, before Forfeiture	158		158			158
Stock Issued During Period, Shares, Employee Stock Purchase Plans		17,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	992		992			992
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	6,292		6,292			6,292
Adjustments to Additional Paid in Capital, Other	(868)							$ (868)
Ending balance (in shares) at Sep. 30, 2018		39,400,000
Ending balance at Sep. 30, 2018	712,332		1,326,719	(185,246)	(449,273)	692,200	20,132
Net income (loss) attributable to noncontrolling interests	$ (95)						(95)
Beginning balance (in shares) at Dec. 31, 2018	39,498,000	39,498,000
Beginning balance at Dec. 31, 2018	$ 734,048		1,334,364	(196,305)	(425,396)	712,663	21,385
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(149)				(1,907)	(1,907)	1,758
Other Comprehensive Income (Loss), Net of Tax	(1,780)			(1,780)		(1,780)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(517)						(517)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		20,000
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	889		889			889
Stock Issued During Period, Shares, Restricted Stock Award, Gross		319,000
Stock Issued During Period, Value, Restricted Stock Award, Gross	(720)		(720)			(720)
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture		2,000
Shares Issued, Value, Share-based Payment Arrangement, before Forfeiture	157		157			157
Stock Issued During Period, Shares, Employee Stock Purchase Plans		19,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	869		869			869
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	$ 7,048		7,048			7,048
Stock Repurchased During Period, Shares	(165,000)
Stock Repurchased During Period, Value	$ (7,814)		(7,814)			(7,814)
Ending balance (in shares) at Mar. 31, 2019		39,693,000
Ending balance at Mar. 31, 2019	732,031		1,334,793	(198,085)	(427,303)	709,405	22,626
Net Income (Loss) Attributable to Parent	$ 34,386
Beginning balance (in shares) at Dec. 31, 2018	39,498,000	39,498,000
Beginning balance at Dec. 31, 2018	$ 734,048		1,334,364	(196,305)	(425,396)	712,663	21,385
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	38,145
Other Comprehensive Income (Loss), Net of Tax	$ (10,749)
Stock Repurchased During Period, Shares	(529,396)
Stock Repurchased During Period, Value	$ (25,000)
Ending balance (in shares) at Sep. 30, 2019	39,533,000	39,533,000
Ending balance at Sep. 30, 2019	$ 761,916		1,335,353	(207,054)	(391,010)	737,289	24,627
Net income (loss) attributable to noncontrolling interests	3,759
Beginning balance (in shares) at Mar. 31, 2019		39,693,000
Beginning balance at Mar. 31, 2019	732,031		1,334,793	(198,085)	(427,303)	709,405	22,626
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	20,117				19,446	19,446	671
Other Comprehensive Income (Loss), Net of Tax	3,736			3,736		3,736
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		39,000
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	1,501		1,501			1,501
Stock Issued During Period, Shares, Restricted Stock Award, Gross		7,000
Stock Issued During Period, Value, Restricted Stock Award, Gross	(920)		(920)			(920)
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture		3,000
Shares Issued, Value, Share-based Payment Arrangement, before Forfeiture	158		158			158
Stock Issued During Period, Shares, Employee Stock Purchase Plans		17,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	742		742			742
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	$ 6,420		6,420			6,420
Stock Repurchased During Period, Shares	(364,000)
Stock Repurchased During Period, Value	$ (17,186)		(17,186)			(17,186)
Ending balance (in shares) at Jun. 30, 2019		39,395,000
Ending balance at Jun. 30, 2019	746,599		1,325,508	(194,349)	(407,857)	723,302	23,297
Net Income (Loss) Attributable to Parent	16,847
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	18,177				16,847	16,847	1,330
Other Comprehensive Income (Loss), Net of Tax	(12,705)			(12,705)		(12,705)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		58,000
Stock Issued, Value, Stock Options Exercised, Net of Tax Benefit (Expense)	2,317		2,317			2,317
Stock Issued During Period, Shares, Restricted Stock Award, Gross		65,000
Stock Issued During Period, Value, Restricted Stock Award, Gross	(552)		(552)			(552)
Shares Issued, Shares, Share-based Payment Arrangement, before Forfeiture		2,000
Shares Issued, Value, Share-based Payment Arrangement, before Forfeiture	158		158			158
Stock Issued During Period, Shares, Employee Stock Purchase Plans		13,000
Stock Issued During Period, Value, Employee Stock Purchase Plan	799		799			799
Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture	$ 7,123		7,123			7,123
Ending balance (in shares) at Sep. 30, 2019	39,533,000	39,533,000
Ending balance at Sep. 30, 2019	$ 761,916		$ 1,335,353	$ (207,054)	$ (391,010)	$ 737,289	$ 24,627
Net income (loss) attributable to noncontrolling interests	$ 1,330