Investments (Details) (WMES, USD $)	1 Months Ended	3 Months Ended	12 Months Ended			36 Months Ended
	Jun. 30, 2011 engine	Mar. 31, 2014 item	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2014 engine	May 25, 2011
Investments
Ownership percentage		50.00%				50.00%
Initial capital contribution							$ 8,000,000
Additional capital contributions			11,200,000	5,600,000	1,000,000
Number of engines transferred to the joint venture	7
Number of engines purchased						17
Capital contributions to date		25,800,000				25,800,000
Credit facility established by equity method investee		62,000,000				62,000,000
Investment in joint venture		23,790,000	23,485,000			23,790,000
Number of engines in lease portfolio		26
Proportionate gain on sale of engines to joint venture interest which is off-set against investments	3,600,000
Net investment after deducting partial offset		22,200,000				22,200,000
Proportionate gain on sale of engines to joint venture interest (as a percent)	50.00%
Gain on sale of engines	7,200,000
JA Mitsui Leasing, Ltd
Investments
Credit facility established by equity method investee		$ 180,000,000				$ 180,000,000