Stockholders' Equity (Components of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 218,453	$ 193,304	$ 171,557
Other comprehensive income (loss), before tax amount	(414)	(1,780)	4,772
Other comprehensive income (loss), tax effect	176	(235)	115
Other comprehensive income (loss)	(238)	(2,015)	4,887
Balance at end of period	241,752	218,453	193,304
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(37,465)	(35,450)	(40,337)
Other comprehensive income (loss)	(238)	(2,015)	4,887
Balance at end of period	(37,703)	(37,465)	(35,450)
Pension and other postretirement actuarial items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(6,146)	(8,060)	(7,145)
Balance at end of period		(6,146)	(8,060)
Pension and other postretirement actuarial items, before reclassifications
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(6,686)	(8,498)
Other comprehensive income (loss), before reclassifications, before tax amount	(1,310)	1,392	(1,465)
Other comprehensive income (loss), before reclassifications, tax	194	(18)	112
Other comprehensive income (loss), before reclassifications, net of tax amount	(1,116)	1,374	(1,353)
Balance at end of period	(7,262)	(6,686)	(8,498)
Reclassification adjustment for recognition of actuarial items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification adjustment, before tax amount	359	685	583
Reclassification adjustment, tax effect	(39)	(145)	(145)
Reclassification adjustment, net of tax amount	320	540	438
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(31,319)	(27,390)	(33,192)
Other comprehensive income (loss), before reclassifications, before tax amount		(3,857)	5,654
Other comprehensive income (loss), before reclassifications, tax		(72)	148
Other comprehensive income (loss), before reclassifications, net of tax amount		(3,929)	5,802
Reclassification adjustment, before tax amount	827
Reclassification adjustment, tax effect	0
Reclassification adjustment, net of tax amount	827
Balance at end of period		$ (31,319)	$ (27,390)
Foreign currency translation adjustment, before reclassifications
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Other comprehensive income (loss), before reclassifications, before tax amount	(290)
Other comprehensive income (loss), before reclassifications, tax	21
Other comprehensive income (loss), before reclassifications, net of tax amount	(269)
Balance at end of period	$ (31,588)