Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Tax benefit from (provision for) actuarial (loss) gain on benefit obligation and plan assets	$ 531	$ 922	$ (597)
Tax benefit from (provision for) amortization of net loss recognized in net periodic benefit cost	(10)	0	(32)
Tax benefit from (provision for) amortization of prior service cost recognized in net periodic benefit cost	(30)	(39)	(8)
Tax benefit from (provision for) settlement	$ (91)	$ (118)	$ 173