Annual report pursuant to Section 13 and 15(d)

Related Person Transactions (Details)

v3.3.1.900
Related Person Transactions (Details) - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Related Party Transaction [Line Items]      
Rental service charge $ 12,000 $ 17,500 $ 18,000
Purchase of maintenance and other services $ 313,000 $ 298,000 $ 299,000