Consolidated Statements of Operations and Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in net unrealized gain (loss) on securities available for sale, tax	$ 29,740	$ 1,560	$ 437
Change in the non-credit portion of OTTI losses recognized in other comprehensive income (loss), tax	13	49	44
Change in pension and post-retirement obligations, tax	2,234	2,924	1,161
Reclassification adjustment for sales of available-for-sale securities, tax	$ 1,245	$ 1,127	$ 306