Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, issued shares	0	0
Common stock, authorized shares	200,000,000	200,000,000
Common stock, issued shares	102,565,266	101,259,800
Common stock, outstanding shares	102,565,266	101,259,800
Nonutility property, plant and equipment, accumulated depreciation	$ 1,227	$ 1,223