Quarterly Results (Unaudited) Quarterly Results Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Results [Line Items]
Revenues	$ 495,713	$ 506,859	$ 513,024	$ 497,590			$ 496,448	$ 469,528	$ 470,811	$ 446,746	$ 2,013,186	$ 1,883,533	$ 1,947,616
Gross Profit	156,663	170,749	169,705	163,203			152,419	147,290	118,554	138,422	660,320	556,685	614,050
Net Income (Loss) Attributable to Parent	$ 11,649	$ (9,885)	$ 19,917	$ 10,089			$ 8,986	$ 12,640	$ (14,346)	$ 5,398	$ 31,770	$ 12,678	$ (23,670)
Earnings (loss) per common share - Basic	$ 0.30	$ (0.26)	$ 0.52	$ 0.27			$ 0.23	$ 0.33	$ (0.37)	$ 0.14	$ 0.83	$ 0.33	$ (0.60)
Earnings (loss) per common share - Diluted	$ 0.30	$ (0.26)	$ 0.52	$ 0.26			$ 0.23	$ 0.33	$ (0.37)	$ 0.14	$ 0.82	$ 0.33	$ (0.60)
Restructuring Charges											$ 49,090	$ (7,263)	$ 49,482
Quarterly Financial Information, Quarterly Charges and Credits, Amount Affecting Comparability					$ 13,300
Warranty Expense											13,920	45,984	9,238
2016 Projects [Member]
Quarterly Results [Line Items]
Restructuring Charges	$ 7,800	$ 40,000									47,794
Water Operating Segment [Member]
Quarterly Results [Line Items]
Revenues											505,336	519,422	576,668
Gross Profit											172,580	$ 145,680	$ 202,178
Warranty Expense						$ 23,600
Water Operating Segment [Member] | 2016 Projects [Member]
Quarterly Results [Line Items]
Restructuring Charges											$ 13,061