Revenue Concentration (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Concentration Risk [Line Items]
Revenues	$ 65,692	$ 66,117	$ 59,366	$ 58,492	$ 58,810	$ 59,203	$ 55,312	$ 54,264	$ 249,667	$ 227,589	$ 212,405
Ten Largest Container Lessees [Member] | Customer Concentration Risk [Member] | Total Revenue [Member]
Concentration Risk [Line Items]
Number of major customers | item									10
Percentage of operations comprised by segment									51.90%	55.40%	56.60%
Single Largest Container Lessee [Member] | Customer Concentration Risk [Member] | Total Revenue [Member]
Concentration Risk [Line Items]
Percentage of operations comprised by segment									11.60%	11.40%	11.20%
Revenues									$ 29,000	$ 25,900	$ 23,800