Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Operating Revenues	$ 213,036	$ 206,983	$ 197,038	$ 213,928	$ 250,631	$ 261,852	$ 281,609	$ 260,644	$ 830,985	$ 1,054,736	$ 1,319,394
Operating Income (Loss)	(99,364)	(33,016)	(30,151)	(10,016)	(928)	28,221	7,499	(13,667)	(172,547)	21,125	165,243
Net Income (Loss)	(90,289)	(34,026)	(50,933)	(20,524)	(49,853)	16,405	(8,501)	(17,901)	(195,772)	(59,850)	124,347
Net Income (Loss) attributable to SEACOR Holdings Inc.	$ (93,749)	$ (39,803)	$ (55,159)	$ (27,186)	$ (56,865)	$ 6,965	$ 687	$ (19,569)	$ (215,897)	$ (68,782)	$ 100,132
Basic Earnings (Loss) Per Common Share of SEACOR Holdings Inc.	$ (5.52)	$ (2.35)	$ (3.26)	$ (1.62)	$ (3.36)	$ 0.40	$ 0.04	$ (1.10)	$ (12.76)	$ (3.94)	$ 5.18
Diluted Earnings (Loss) Per Common Share of SEACOR Holdings Inc.	$ (5.52)	$ (2.35)	$ (3.26)	$ (1.62)	$ (3.36)	$ 0.40	$ 0.04	$ (1.10)	$ (12.76)	$ (3.94)	$ 4.71