Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accumulated depreciation on flight equipment held for lease	$ 1,278,438	$ 1,224,899
Common shares, par value	$ 0.01	$ 0.01
Common shares, shares authorized	250,000,000	250,000,000
Common shares, shares issued	78,713,706	78,593,133
Common shares, shares outstanding	78,713,706	78,593,133
Preference shares, par value	$ 0.01	$ 0.01
Preference shares, shares authorized	50,000,000	50,000,000