Fair Value Measurements - Nonrecurring Basis (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) engine	Dec. 31, 2017 USD ($) engine aircraft	Dec. 31, 2016 USD ($)
Assets at fair value and gains (losses) recorded
Equipment held for sale	$ 789	$ 34,172
Assets at fair value	1,700	1,100
Asset write-down	$ 10,651	$ 24,930	$ 9,514
Engine Parts
Assets at fair value and gains (losses) recorded
Number of engines | engine	7	9
Aircrafts
Assets at fair value and gains (losses) recorded
Number of aircraft | aircraft		5
Asset write-down		$ 4,700
Nonrecurring
Assets at fair value and gains (losses) recorded
Equipment held for lease	$ 17,756	23,255
Equipment held for sale	472	39,261
Assets at fair value	18,228	62,516
Total losses on equipment held for lease	(8,893)	(12,879)
Total losses on equipment held for sale	(1,758)	(12,051)
Total losses on assets	(10,651)	(24,930)
Inventory Write-down	1,800
Nonrecurring | Engine Parts
Assets at fair value and gains (losses) recorded
Asset write-down	8,900	16,900
Nonrecurring | Level 2
Assets at fair value and gains (losses) recorded
Equipment held for lease	17,756	23,255
Equipment held for sale	472	39,261
Assets at fair value	$ 18,228	$ 62,516
Engines and Related Equipment
Assets at fair value and gains (losses) recorded
Number of engines | engine	34