Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Property, plant and equipment, net	$ 1,962,637	$ 1,959,578
Construction-in-process	352,013	261,690
Operating leases right of use	58,170	0
Finance leases right of use	$ 18,046	$ 0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	50,993,861	50,699,781
Common stock, shares outstanding (in shares)	50,993,861	50,699,781
Senior Secured Notes [Member]
Deferred financing costs	$ 6,597	$ 7,434
Other Loans, Limited and Non-recourse [Member]
Deferred financing costs	10,797	9,354
Senior Unsecured Bonds [Member]
Deferred financing costs	727	758
Other Loans, Full Recourse [Member]
Deferred financing costs	1,564	921
Variable Interest Entity, Primary Beneficiary [Member]
Property, plant and equipment, net	1,860,656	1,859,228
Construction-in-process	163,187	$ 104,085
Operating leases right of use	49,079
Finance leases right of use	$ 9,246