Segments - Revenue and Assets by Country (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Rental revenue	$ 77,246	$ 62,442	$ 62,855	$ 61,492	$ 68,688	$ 64,082	$ 55,842	$ 57,685	$ 264,035	$ 246,297	$ 203,767
Assets	815,284				691,556				815,284	691,556
United States
Segment Reporting Information [Line Items]
Rental revenue									257,297	237,815	193,600
Assets	802,516				669,942				802,516	669,942
Canada
Segment Reporting Information [Line Items]
Rental revenue									5,705	6,297	8,583
Assets	8,152				11,923				8,152	11,923
Mexico
Segment Reporting Information [Line Items]
Rental revenue									1,033	2,185	$ 1,584
Assets	$ 4,616				$ 9,691				$ 4,616	$ 9,691