Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 30,086	$ (13,878)
Other comprehensive income (loss):
Amortization of accumulated actuarial gains or losses, pension	818	1,110
Adjustments to accumulated actuarial losses and transition obligations, pension	172	203
Amortization of accumulated actuarial gains or losses, transition obligations, and prior service costs, postretirement medical benefit	200	327
Adjustments of accumulated actuarial losses and transition obligations, postretirement medical benefit	(688)	0
Tax effect of other comprehensive income gains	(57)	(575)
Change in foreign currency translation adjustment	19,239	(27,140)
Unrealized and realized gains and losses on available-for-sale securities	(281)	325
Other comprehensive income (loss)	19,403	(25,750)
Comprehensive loss attributable to the Parent company	$ 49,489	$ (39,628)