Cash flow information (Details) - USD ($)		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017
Interest, net	[1]	$ 39,467,000	$ 39,207,000
Income taxes paid, net	[2]	4,034,000	32,388,000
AFUDC borrowed		1,000,000.0	418,000
Property, plant and equipment additions in accounts payable		30,985,000	10,449,000
Issuance of common stock in connection with acquisition		17,993,000	0
Continuing and discontinued operations
Income taxes paid, net		$ 3,100,000	$ (3,600,000)

[1] AFUDC - borrowed was $1.0 million and $418,000 for the six months ended June 30, 2018 and 2017, respectively.

[2] Income taxes paid (refunded), net of discontinued operations, were $3.1 million and $(3.6) million for the six months ended June 30, 2018 and 2017, respectively.