Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, plant and equipment, net	$ 1,734,691	$ 1,556,378
Construction-in-process	$ 293,542	$ 306,709
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)	50,609,051	49,667,340
Common stock, shares outstanding (in shares)	50,609,051	49,667,340
Senior Secured Notes [Member]
Deferred financing costs	$ 8,113	$ 9,177
Other Loans, Limited and Non-recourse [Member]
Deferred financing costs	5,258	6,409
Senior Unsecured Bonds [Member]
Deferred financing costs	580	755
Other Loans, Full Recourse [Member]
Deferred financing costs	1,011	1,346
Variable Interest Entity, Primary Beneficiary [Member]
Property, plant and equipment, net	1,631,900	1,483,224
Construction-in-process	$ 142,717	$ 120,853