Consolidated Statements Of Changes In Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Non-Controlling Interests In Subsidiaries [Member]
Total equity	$ 1,517,487	$ 375	$ 1,490,698	$ 1,195,402	$ (1,283,476)	$ (3,505)	$ 117,993
Issuance of common stock:
Employee Stock Purchase Plan	2,298	0	0	0	2,298	0	0
Exercise of stock options	1,948	1	1,947	0	0	0	0
Director stock awards	234	0	234	0	0	0	0
Restricted stock and restricted stock units	123	(1)	145	0	(21)	0	0
Distribution of Dorian shares to shareholders	0
Issuance of conversion option in convertible debt, net of tax	(1,938)	0	(1,938)	0	0	0	0
Purchase of treasury shares	(75,342)	0	0	0	(75,342)	0	0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	14,649	0	14,649	0	0	0	0
Purchase of subsidiary shares from noncontrolling interests, net of tax	497	0	497	0	0	0	0
Disposition of subsidiary with noncontrolling interests	(1,578)	0	0	0	0	0	(1,578)
Issuance of noncontrolling interests	400	0	0	0	0	0	400
Dividends paid to noncontrolling interests	5,199	0	0	0	0	0	5,199
Comprehensive income:
Net Income attributable to SEACOR Holdings Inc.	(68,782)	0	0		0	0
Net Income (Loss) Attributable to Noncontrolling Interest	8,932
Net Income (Loss)	(59,850)
Other Comprehensive Loss, Net of Tax	(2,544)	0	0	0	0	(2,115)	(429)
Total equity	1,390,939	377	1,505,942	1,126,620	(1,356,499)	(5,620)	120,119
Employee Stock Purchase Plan	1,726	0	0	0	1,726	0	0
Exercise of stock options	4,368	1	4,367	0	0	0	0
Director stock awards	186	0	186	0	0	0	0
Restricted stock and restricted stock units	(1,179)	(1)	(1,180)	0	0	0	0
Distribution of Dorian shares to shareholders	0
Purchase of conversion option in convertible debt, net of tax	4,793	0	4,793	0	0	0	0
Purchase of treasury shares	(2,396)	0	0	0	(2,396)	0	0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	13,951	0	13,951	0	0	0	0
Cancellation of restricted stock	0	0	162	0	(162)	0	0
Dividends paid to noncontrolling interests	3,753	0	0	0	0	0	3,753
Net Income attributable to SEACOR Holdings Inc.	(215,897)	0	0		0	0
Net Income (Loss) Attributable to Noncontrolling Interest	20,125
Net Income (Loss)	(195,772)
Other Comprehensive Loss, Net of Tax	(7,009)	0	0	0	0	(5,894)	(1,115)
Total equity	1,196,268	379	1,518,635	910,723	(1,357,331)	(11,514)	135,376
Employee Stock Purchase Plan	1,443	0	0	0	1,443	0	0
Exercise of stock options	21,154	6	21,148	0	0	0	0
Director stock awards	83	0	83	0	0	0	0
Restricted stock and restricted stock units	0	(2)	(2)	0	0	0	0
Exercise of conversion option in convertible debt	3	0	3	0	0	0	0
Distribution of SEACOR Marine stock to shareholders	(527,691)	0	2,656	(521,859)	0	10,125	(18,613)
Distribution of Dorian shares to shareholders	(31,379)	0	0	(31,379)	0	0	0
Purchase of conversion option in convertible debt, net of tax	(927)	0	(927)	0	0	0	0
Purchase of treasury shares	(12,300)	0	0	0	(12,300)	0	0
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	32,419	0	32,419	0	0	0	0
Cancellation of restricted stock	0	0	112	0	112	0	0
Purchase of subsidiary shares from noncontrolling interests, net of tax	3,693	0	1,114	0	0	0	2,579
Acquisition of a subsidiary with noncontrolling interests	17,374	0	0	0	0	0	17,374
Disposition of subsidiary with noncontrolling interests	(14,673)	0	0	0	0	0	(14,673)
Dividends paid to noncontrolling interests	7,434	0	0	0	0	0	7,434
Net Income attributable to SEACOR Holdings Inc.	61,643	0	0		0	0
Net Income (Loss) Attributable to Noncontrolling Interest	20,066
Net Income (Loss)	81,709
Other Comprehensive Loss, Net of Tax	1,005	0	0	0	0	844	161
Total equity	$ 753,361	$ 387	$ 1,573,013	$ 419,128	$ (1,368,300)	$ (545)	$ 129,678