CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) [Abstract]
Net earnings (loss) available to common stockholders	$ 9,710	$ 4,920	$ (68,211)	$ 16,302
Other comprehensive income (loss):
Currency translation adjustment, net of taxes of ($111) in the three months ended September 30, 2016, $0 in the three months ended September 30, 2015, ($456) in the nine months ended September 30, 2016 and ($194) in the nine months ended September 30, 2015	(156)	(1,439)	(3,199)	(8,240)
Increase (decrease) in unrealized gains on marketable securities arising during the period, net of taxes of $15 in the three months ended September 30, 2016, ($54) in the three months ended September 30, 2015, $74 in the nine months ended September 30,2016 and ($39) in the nine months ended September 30, 2015	14	(89)	112	(64)
Change in unfunded SERP liability, net of taxes of $32 in the three months ended September 30, 2016, $28 in the three months ended September 30, 2015, $136 in the nine months ended September 30, 2016 and $84 in the nine months ended September 30, 2015	65	63	566	191
Other comprehensive loss	(77)	(1,465)	(2,521)	(8,113)
Comprehensive income (loss)	$ 9,633	$ 3,455	$ (70,732)	$ 8,189