Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accumulated depreciation	$ 11,629	$ 11,356
Receivables, allowances	$ 1,091	$ 1,372
Redeemable preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Redeemable preferred stock, shares authorized (in shares)	2,500,000	2,500,000
Redeemable preferred stock, shares issued (in shares)	2,500,000	2,500,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares issued (in shares)	6,577,000	6,570,000
Accumulated other comprehensive loss, income tax benefit	$ 788	$ (1,428)
Restricted cash	38,274	36,385
Maintenance rights	20,097	20,097
Spare parts inventory	57,870	59,434
Notes receivable	197,552	158,708
Other assets	49,631	43,778
Debt obligations	1,724,130	1,693,753
Variable Interest Entity
Restricted cash	33,763	35,262
Equipment	1,025,492	1,037,684
Maintenance rights	767	767
Spare parts inventory	5,437	5,437
Notes receivable	26,220	26,392
Other assets	604	558
Debt obligations	898,398	907,550
Assets Leased to Others
Accumulated depreciation	$ 477,584	$ 454,123