CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Interest rate swaps, deferred tax expense	$ 300	$ 1,300	$ 1,000
Capitalized swap interest, deferred tax benefit	100	100	100
Pension adjustment, tax	$ 0	$ (543)	$ 0