Dispositions (Narrative) (Details) - USD ($) $ in Thousands				1 Months Ended	3 Months Ended						10 Months Ended		12 Months Ended
		Mar. 01, 2016	Oct. 07, 2015	Jan. 31, 2015	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2016		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014	Oct. 01, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash consideration from disposal	[1]												$ 873,920		$ 49,906	$ 0
Amortization of deferred gains	[2]				$ 82,271
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Assurant Employee Benefits
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net cash consideration from disposal		$ 926,174
Consideration from disposal consisting of account renewals	[2]	16,000
Estimated gain disposal before adjustment		638,517
Estimated gain (loss) on disposal		656,497						$ 656,497
Gain (loss) net of tax		120,077
Deferred gain on disposal, before adjustment		518,440
Deferred gain on disposal		$ 520,420			153,865	[3]					$ 153,865	[3]	153,865	[3]
Amortization of deferred gains	[2]						$ 116,856	$ 122,835	$ 44,593				366,555
Gain (loss) on disposal													502,632
Percent of deferred gain to be earned (over)											90.00%
Pretax income from disposal													13,709		73,809	76,781
Disposal Group, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of subsidiary			$ 19,600
Disposal Group, Not Discontinued Operations | Other Income
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of assets										$ 16,773
Disposal Group, Not Discontinued Operations | Assurant Health Supplemental and Small-Group Self-Funded Line of Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred gain on disposal																	$ 5,336
Cash consideration for line of business sold																	$ 14,000
Disposal Group, Not Discontinued Operations | Assurant Health Supplemental and Small-Group Self-Funded Line of Business | Selling, General and Administrative Expenses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on disposition of supplemental business										$ 11,587
Disposal Group, Not Discontinued Operations | American Reliable Insurance Company (ARIC)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of subsidiary				$ 117,860
Contingent liability related to disposal					$ 23,000						$ 23,000		$ 23,000
Disposal Group, Not Discontinued Operations | American Reliable Insurance Company (ARIC) | Selling, General and Administrative Expenses
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal															$ 1,120	$ (21,526)

[1] 2016 includes the sale of Assurant's Employee Benefits segment mainly through reinsurance transactions and supplemental and small group self-funded business; the acquisition of American Title and the purchase of renewal rights to the National Flood Insurance block of business of Nationwide Mutual Insurance Company and other immaterial subsidiaries. 2015 includes the sale of American Reliable Insurance Co. and certain assets related to our vehicle title administration services business and supplemental and small group self-funded businesses; the acquisition of Coast to Coast Services, Inc. and Rent Collect Global. 2014 includes the acquisition of StreetLinks, LLC, eMortgage Logic, LLC, CWI Group and other immaterial subsidiaries.

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

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