Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Goodwill and other intangible assets
Net book value	$ 17,085	$ 20,087
Empower Retirement Segment
Goodwill and other intangible assets
Gross carrying amount	47,942	48,905
Accumulated amortization	(30,857)	(28,818)
Net book value	17,085	20,087
Empower Retirement Segment \| Customer relationships
Goodwill and other intangible assets
Gross carrying amount	47,580	47,580
Accumulated amortization	(30,495)	(27,517)
Net book value	17,085	20,063
Empower Retirement Segment \| Non-competition
Goodwill and other intangible assets
Gross carrying amount	362	1,325
Accumulated amortization	(362)	(1,301)
Net book value	$ 0	$ 24

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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