Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Accumulated depreciation on flight equipment held for lease	$ 1,228,052	$ 981,932
Borrowings from secured and unsecured financings	3,079,554	2,986,516
Preference shares, par value	$ 0.01	$ 0.01
Preference shares, shares authorized	50,000,000	50,000,000
Preference shares, shares issued
Preference shares, shares outstanding
Common shares, par value	$ 0.01	$ 0.01
Common shares, shares authorized	250,000,000	250,000,000
Common shares, shares issued	69,743,929	72,258,472
Common shares, shares outstanding	69,743,929	72,258,472
ACS Ireland VIEs
Borrowings from secured and unsecured financings	$ 217,541	$ 295,952