Other Long-Term Assets (Schedule of Other Long-Term Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Long-term assets:
Advance coal royalties	$ 5,554		$ 5,496
Deferred financing costs, net	6,158		6,507
Marketable equity securities available for sale, at fair value (restricted)*	2,084	[1]	2,249	[1]
Other	3,023		4,597
Long-term assets	$ 16,819		$ 18,849

[1] Held by Sunrise Indemnity, Inc., our wholly-owned captive insurance company.