Earnings (Loss) per Common Share - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Interest expense and deferred financing fees	$ 0	$ 1,049	$ 3,222

The after-tax amount of interest recognized in the period associated with any convertible debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=96947427&loc=d3e1505-109256

Name:	us-gaap_InterestOnConvertibleDebtNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration