The following table displays a rollforward of the carrying amount of goodwill from January 1, 2015 to December 31, 2016 (in thousands):
Balance as of January 1, 2015
$
88,959

Additions
56,992

Disposals
(577
)
Balance as of December 31, 2015
145,374

Disposals
(17,854
)
Impairment
(3,636
)
Balance as of December 31, 2016
$
123,884