Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 137,683,000	$ 137,683,000
Amortization expense included in general insurance expenses	3,732,000	4,096,000	$ 3,531,000
Intangible assets with indefinite lives	0
2017	2,200,000
2018	2,200,000
2019	2,200,000
2020	2,200,000
2021	2,200,000
Empower Retirement Segment
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 137,683,000	$ 137,683,000