Employee Benefit Plans - Summary of amounts recognized in consolidated balance sheets (Details 1) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Long-term pension liability	$ (33,009)	$ (34,399)
Retirement Income Plan
Defined Benefit Plan Disclosure [Line Items]
Funded status	(11,957)	(14,788)
SERP liability	(21,052)	(19,611)
Long-term pension liability	$ (33,009)	$ (34,399)