Segment Information - Segment Results Narrative (Details) $ / shares in Units, $ in Millions	3 Months Ended																9 Months Ended	12 Months Ended
	Dec. 31, 2018 $ / shares	[1]	Sep. 30, 2018 $ / shares	[1]	Jun. 30, 2018 $ / shares	[1]	Mar. 31, 2018 $ / shares	[1]	Dec. 31, 2017 $ / shares	[1]	Sep. 30, 2017 $ / shares	[1]	Jun. 30, 2017 $ / shares	[1]	Mar. 31, 2017 $ / shares	[1]	Sep. 30, 2018	Dec. 31, 2018 $ / shares		Dec. 31, 2017 USD ($) $ / shares		Dec. 31, 2016 $ / shares
Segment Reporting Information [Line Items]
Number of reportable segments																	4
Number of operating segments																		3		4		3
Unusual or infrequent item, or both, insurance proceeds | $																				$ 8.0
Earnings (loss) per common share - Basic (in dollars per share)	$ 0.61		$ 0.51		$ 0.07		$ (3.74)		$ 0.05		$ 0.66		$ 0.36		$ 0.41			$ (2.53)	[1]	$ 1.48	[1]	$ 0.83
Earnings (loss) per common share - Diluted (in dollars per share)	$ 0.60		$ 0.50		$ 0.07		$ (3.74)		$ 0.05		$ 0.65		$ 0.36		$ 0.40			$ (2.53)	[1]	1.45	[1]	$ 0.82
Insurance Recovery, net of tax [Member] | Water Operating Segment [Member]
Segment Reporting Information [Line Items]
Earnings (loss) per common share - Basic (in dollars per share)																				0.13
Earnings (loss) per common share - Diluted (in dollars per share)																				$ 0.12
Sales [Member] | Threshold for Reporting Customer Concentration [Member]
Segment Reporting Information [Line Items]
Percentage of total company revenue represented by one customer																		10.00%		10.00%		10.00%

[1] The sum of the quarterly EPS data presented in the table may not equal the annual results due to rounding and the impact of dilutive securities on the annual versus the quarterly EPS calculations.