CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Current assets
Accounts receivable, allowance for doubtful accounts	$ 2,110	$ 1,440
Rental equipment net of accumulated depreciation	2,218,212	2,004,961
Rental equipment, accumulated depreciation	550,426	505,546
Net investment in direct finance leases	275,826	246,450
Intangible assets, accumulated amortization	4,495	3,407
Furniture, fixtures and equipment, accumulated depreciation	3,265	3,201
Current liabilities
Current portion of debt	159,599	132,049
Debt	$ 1,679,492	$ 1,570,773
Stockholders' equity
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred Stock, Dividend Rate, Percentage	8.50%	8.50%
Preferred stock, shares authorized	10,000,000	5,000,000
Preferred stock, shares issued	2,199,610	0
Preferred stock, shares outstanding	2,199,610	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	84,000,000	84,000,000
Common stock, shares issued	19,306,377	20,390,622
Common stock, shares outstanding	19,306,377	20,390,622
Variable Interest Entity, Primary Beneficiary [Member]
Current assets
Cash	$ 24,348	$ 20,685
Rental equipment net of accumulated depreciation	62,320	61,842
Net investment in direct finance leases	9,004	4,423
Current liabilities
Current portion of debt	30,237	22,549
Debt	$ 68,560	$ 72,727