Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Property, plant and equipment, net	$ 1,963,086,000	$ 1,959,578,000
Construction-in-process	306,810,000	261,690,000
Finance leases right of use	$ 15,469,000	$ 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)	50,862,581	50,699,781
Common stock, shares outstanding (in shares)	50,862,581	50,699,781
Senior Secured Notes [Member]
Deferred financing costs	$ 6,869,000	$ 7,434,000
Other Loans, Limited and Non-recourse [Member]
Deferred financing costs	11,018,000	9,354,000
Senior Unsecured Bonds [Member]
Deferred financing costs	779,000	758,000
Other Loans, Full Recourse [Member]
Deferred financing costs	1,612,000	921,000
Variable Interest Entity, Primary Beneficiary [Member]
Property, plant and equipment, net	1,863,523,000	1,859,228,000
Construction-in-process	134,519,000	104,085,000
Finance leases right of use	$ 8,992,000