Accumulated Other Comprehensive Loss (After-tax Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	$ (5,347)		$ (11,993)	$ (2,700)		$ (12,468)
Other comprehensive income (loss) before reclassifications	[1]	1,097		2,453	(1,286)		2,928
Amounts reclassified from accumulated other comprehensive loss	[1]	(114)		(142)	(378)		(142)
Net current-period other comprehensive income (loss)	[1]	983		2,311	(1,664)		2,786
Ending balance	[1]	(4,364)		(9,682)	(4,364)		(9,682)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	51			0
Other comprehensive income (loss) before reclassifications	[1]	65			44
Amounts reclassified from accumulated other comprehensive loss		54			126
Net current-period other comprehensive income (loss)	[1]	119			170
Ending balance	[1]	170			170
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	(9,989)		(9,529)	(7,716)		(11,002)
Other comprehensive income (loss) before reclassifications	[1]	993		2,201	(1,280)		3,674
Amounts reclassified from accumulated other comprehensive loss	[1]	0		0	0		0
Net current-period other comprehensive income (loss)	[1]	993		2,201	(1,280)		3,674
Ending balance	[1]	(8,996)		(7,328)	(8,996)		(7,328)
Investment in Convertible Preferred Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		257	[1]	0	344	[1]	0	[1]
Other comprehensive income (loss) before reclassifications		0	[1]	211	(87)	[1]	211	[1]
Amounts reclassified from accumulated other comprehensive loss		0	[1]	0	0	[1]	0	[1]
Net current-period other comprehensive income (loss)		0	[1]	211	(87)	[1]	211	[1]
Ending balance	[1]	257		211	257		211
Defined Benefit Plan Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	[1]	4,334		(2,464)	4,672		(1,466)
Other comprehensive income (loss) before reclassifications	[1]	39		41	37		(957)
Amounts reclassified from accumulated other comprehensive loss	[1]	(168)		(142)	(504)		(142)
Net current-period other comprehensive income (loss)	[1]	(129)		(101)	(467)		(1,099)
Ending balance	[1]	$ 4,205		$ (2,565)	$ 4,205		$ (2,565)

[1] All amounts are net of tax. Amounts in parentheses indicate debits