Dispositions (Gain by Transaction Component) (Details) - USD ($) $ in Thousands				3 Months Ended					12 Months Ended
		Mar. 01, 2016		Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016
Disposal Group, Deferred Gain on Disposal [Roll Forward]
Amortization of deferred gain for the three months ended	[1]			$ 82,271
Assurant Employee Benefits | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total expected gains, after adjustment and contingent consideration		$ 656,497					$ 656,497
Gain on sale of entities, net of transaction costs		41,098
Novations, resulting in recognized gains	[2]	60,913
Loss on retroactive reinsurance component, before realized gains	[3]	(128,661)
Net loss prior to realized gains on transferred securities supporting retroactive component	[4]	(26,650)
Realized gains on transferred securities supporting retroactive component		146,727	[3]						$ 146,727
Gain (loss) net of tax		120,077
Consideration from disposal consisting of account renewals	[1]	16,000
Disposal Group, Deferred Gain on Disposal [Roll Forward]
Amortization of deferred gain for the three months ended	[1]					$ 116,856	$ 122,835	$ 44,593	366,555
Deferred gains as of September 30, 2016		$ 520,420		$ 153,865	[5]				153,865	[5]
Total net gains realized for 2016									$ 502,632

[1] Amount classified as amortization of deferred gains and gains on disposal of businesses within the consolidated statements of operations.

[2] Novations of certain insurance policies directly to Sun Life allowed for immediate gain recognition.

[3] Reinsurance of existing claims liabilities requires retroactive accounting necessitating losses to be recognized immediately. However, upon transfer of the associated assets supporting the liabilities, the Company recognized realized gains which more than offset the retroactive losses. The Company was required to classify the realized gains as part of net realized gains on investments, within the consolidated statements of operations.

[4] Amount classified within underwriting, general and administrative expenses within the consolidated statements of operations.

[5] Amount classified as a component of the deferred gains on disposal of businesses within the consolidated balance sheets.