Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Tax benefit related to change in unrecognized pension and postretirement liability benefit costs	$ (3,669)	$ 0	$ 8,449