CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per common share (in dollars per share)	$ 0.36	$ 0.36	$ 0.28
Change in fair value of derivative instruments, tax benefit			$ 54
Pension liability adjustment, tax (expense) benefit	$ (5,676)	$ 678	$ (394)