Investments (Tables)

3 Months Ended

Mar. 31, 2017

Investment in Marketable Securities [Abstract]

Investments

	At March 31, 2017
In thousands	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Estimated Fair Value
Kootenay Silver, Inc.	$	2,167	$	—		$	—	$	2,167
Rockhaven Resources Ltd	514		(64		)	—		450
Silver Bull Resources, Inc.	131		—			356		487
Other	193		—			499		692
Equity securities	$	3,005	$	(64	)	$	855	$	3,796

	At December 31, 2016
In thousands	Cost		Gross Unrealized Losses		Gross Unrealized Gains		Estimated Fair Value
Kootenay Silver, Inc.	$	2,645	$	—	$	—	$	2,645
Silver Bull Resources, Inc.	233		—		783		1,016
Other	229		—		598		827
Equity securities	$	3,107	$	—	$	1,381	$	4,488

Schedule of Unrealized Loss on Investments [Table Text Block]

The following table summarizes unrealized losses on equity securities for which other-than-temporary impairments have not been recognized and the fair values of those securities, aggregated by the length of time the individual securities have been in a continuous unrealized loss position, at March 31, 2017:

	Less than twelve months					Twelve months or more				Total
In thousands	Unrealized Losses			Fair Value		Unrealized Losses		Fair Value		Unrealized Losses			Fair Value
Equity securities	$	(64	)	$	450	$	—	$	—	$	(64	)	$	450