CONSOLIDATING FINANCIAL STATEMENTS (Balance Sheets) (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CURRENT ASSETS
Cash and cash equivalents	$ 92,785,000	$ 112,653,000
Accounts receivable, less allowance for doubtful accounts	37,793,000	27,693,000
Inventory	19,993,000	24,141,000
Prepaid expenses	16,436,000	15,993,000
Assets held for sale	24,552,000	0
Other current assets	4,935,000	3,047,000
Total current assets	196,494,000	183,527,000
TIMBER AND TIMBERLANDS, NET OF DEPLETION AND AMORTIZATION	2,424,675,000	2,462,066,000
HIGHER AND BETTER USE TIMBERLANDS AND REAL ESTATE DEVELOPMENT COSTS	87,702,000	80,797,000
NET PROPERTY, PLANT AND EQUIPMENT	23,176,000	23,378,000
RESTRICTED CASH	84,903,000	59,703,000
INVESTMENT IN SUBSIDIARIES	0	0
INTERCOMPANY NOTES RECEIVABLE	0	0
OTHER ASSETS	61,422,000	49,010,000
TOTAL ASSETS	2,878,372,000	2,858,481,000
CURRENT LIABILITIES
Accounts payable	27,082,000	25,148,000
Current maturities of long-term debt (Note 5)	0	3,375,000
Accrued taxes	3,583,000	3,781,000
Accrued payroll and benefits	3,760,000	9,662,000
Accrued interest	8,100,000	5,054,000
Deferred revenue	7,901,000	9,721,000
Other current liabilities	15,091,000	11,807,000
Total current liabilities	65,517,000	68,548,000
Long-term debt, net of deferred financing costs	996,145,000	1,022,004,000
PENSION AND OTHER POSTRETIREMENT BENEFITS	31,137,000	31,905,000
OTHER NON-CURRENT LIABILITIES	49,400,000	43,084,000
INTERCOMPANY PAYABLE	0	0
TOTAL RAYONIER INC. SHAREHOLDERS’ EQUITY	1,631,773,000	1,593,023,000
Noncontrolling interest	104,400,000	99,917,000
TOTAL SHAREHOLDERS’ EQUITY	1,736,173,000	1,692,940,000	$ 1,496,752,000
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	2,878,372,000	2,858,481,000
Consolidating Adjustments
CURRENT ASSETS
Cash and cash equivalents	0	0
Accounts receivable, less allowance for doubtful accounts	0	0
Inventory	0	0
Prepaid expenses	0	0
Assets held for sale	0
Other current assets	0	0
Total current assets	0	0
TIMBER AND TIMBERLANDS, NET OF DEPLETION AND AMORTIZATION	0	0
HIGHER AND BETTER USE TIMBERLANDS AND REAL ESTATE DEVELOPMENT COSTS	0	0
NET PROPERTY, PLANT AND EQUIPMENT	0	0
RESTRICTED CASH	0	0
INVESTMENT IN SUBSIDIARIES	(4,406,388,000)	(4,345,564,000)
INTERCOMPANY NOTES RECEIVABLE	0	0
OTHER ASSETS	0	0
TOTAL ASSETS	(4,406,388,000)	(4,345,564,000)
CURRENT LIABILITIES
Accounts payable	0	0
Current maturities of long-term debt (Note 5)		0
Accrued taxes	0	0
Accrued payroll and benefits	0	0
Accrued interest	0	0
Deferred revenue	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Long-term debt, net of deferred financing costs	0	0
PENSION AND OTHER POSTRETIREMENT BENEFITS	0	0
OTHER NON-CURRENT LIABILITIES	0	0
INTERCOMPANY PAYABLE	0	0
TOTAL RAYONIER INC. SHAREHOLDERS’ EQUITY	(4,406,388,000)	(4,345,564,000)
Noncontrolling interest	0	0
TOTAL SHAREHOLDERS’ EQUITY	(4,406,388,000)	(4,345,564,000)
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	(4,406,388,000)	(4,345,564,000)
Rayonier Inc. (Parent Issuer) | Reportable Legal Entities
CURRENT ASSETS
Cash and cash equivalents	34,837,000	48,564,000
Accounts receivable, less allowance for doubtful accounts	1,995,000	0
Inventory	0	0
Prepaid expenses	0	0
Assets held for sale	0
Other current assets	0	0
Total current assets	36,832,000	48,564,000
TIMBER AND TIMBERLANDS, NET OF DEPLETION AND AMORTIZATION	0	0
HIGHER AND BETTER USE TIMBERLANDS AND REAL ESTATE DEVELOPMENT COSTS	0	0
NET PROPERTY, PLANT AND EQUIPMENT	0	0
RESTRICTED CASH	0	0
INVESTMENT IN SUBSIDIARIES	1,583,443,000	1,531,156,000
INTERCOMPANY NOTES RECEIVABLE	43,396,000	40,067,000
OTHER ASSETS	2,000	2,000
TOTAL ASSETS	1,663,673,000	1,619,789,000
CURRENT LIABILITIES
Accounts payable	0	0
Current maturities of long-term debt (Note 5)		0
Accrued taxes	0	0
Accrued payroll and benefits	0	0
Accrued interest	6,094,000	3,047,000
Deferred revenue	0	0
Other current liabilities	1,995,000	0
Total current liabilities	8,089,000	3,047,000
Long-term debt, net of deferred financing costs	323,526,000	323,434,000
PENSION AND OTHER POSTRETIREMENT BENEFITS	0	0
OTHER NON-CURRENT LIABILITIES	0	0
INTERCOMPANY PAYABLE	(299,715,000)	(299,715,000)
TOTAL RAYONIER INC. SHAREHOLDERS’ EQUITY	1,631,773,000	1,593,023,000
Noncontrolling interest	0	0
TOTAL SHAREHOLDERS’ EQUITY	1,631,773,000	1,593,023,000
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	1,663,673,000	1,619,789,000
Subsidiary Guarantors | Reportable Legal Entities
CURRENT ASSETS
Cash and cash equivalents	18,651,000	25,042,000
Accounts receivable, less allowance for doubtful accounts	946,000	3,726,000
Inventory	0	0
Prepaid expenses	882,000	759,000
Assets held for sale	0
Other current assets	216,000	14,000
Total current assets	20,695,000	29,541,000
TIMBER AND TIMBERLANDS, NET OF DEPLETION AND AMORTIZATION	0	0
HIGHER AND BETTER USE TIMBERLANDS AND REAL ESTATE DEVELOPMENT COSTS	0	0
NET PROPERTY, PLANT AND EQUIPMENT	17,693,000	21,000
RESTRICTED CASH	0	0
INVESTMENT IN SUBSIDIARIES	2,822,945,000	2,814,408,000
INTERCOMPANY NOTES RECEIVABLE	(627,022,000)	(628,167,000)
OTHER ASSETS	26,471,000	12,680,000
TOTAL ASSETS	2,260,782,000	2,228,483,000
CURRENT LIABILITIES
Accounts payable	3,453,000	2,838,000
Current maturities of long-term debt (Note 5)		0
Accrued taxes	7,000	48,000
Accrued payroll and benefits	2,074,000	5,298,000
Accrued interest	2,000,000	1,995,000
Deferred revenue	0	0
Other current liabilities	546,000	564,000
Total current liabilities	8,080,000	10,743,000
Long-term debt, net of deferred financing costs	648,619,000	663,570,000
PENSION AND OTHER POSTRETIREMENT BENEFITS	31,821,000	32,589,000
OTHER NON-CURRENT LIABILITIES	7,780,000	9,386,000
INTERCOMPANY PAYABLE	(18,961,000)	(18,961,000)
TOTAL RAYONIER INC. SHAREHOLDERS’ EQUITY	1,583,443,000	1,531,156,000
Noncontrolling interest	0	0
TOTAL SHAREHOLDERS’ EQUITY	1,583,443,000	1,531,156,000
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	2,260,782,000	2,228,483,000
Non- guarantors | Reportable Legal Entities
CURRENT ASSETS
Cash and cash equivalents	39,297,000	39,047,000
Accounts receivable, less allowance for doubtful accounts	34,852,000	23,967,000
Inventory	19,993,000	24,141,000
Prepaid expenses	15,554,000	15,234,000
Assets held for sale	24,552,000
Other current assets	4,719,000	3,033,000
Total current assets	138,967,000	105,422,000
TIMBER AND TIMBERLANDS, NET OF DEPLETION AND AMORTIZATION	2,424,675,000	2,462,066,000
HIGHER AND BETTER USE TIMBERLANDS AND REAL ESTATE DEVELOPMENT COSTS	87,702,000	80,797,000
NET PROPERTY, PLANT AND EQUIPMENT	5,483,000	23,357,000
RESTRICTED CASH	84,903,000	59,703,000
INVESTMENT IN SUBSIDIARIES	0	0
INTERCOMPANY NOTES RECEIVABLE	583,626,000	588,100,000
OTHER ASSETS	34,949,000	36,328,000
TOTAL ASSETS	3,360,305,000	3,355,773,000
CURRENT LIABILITIES
Accounts payable	23,629,000	22,310,000
Current maturities of long-term debt (Note 5)		3,375,000
Accrued taxes	3,576,000	3,733,000
Accrued payroll and benefits	1,686,000	4,364,000
Accrued interest	6,000	12,000
Deferred revenue	7,901,000	9,721,000
Other current liabilities	12,550,000	11,243,000
Total current liabilities	49,348,000	54,758,000
Long-term debt, net of deferred financing costs	24,000,000	35,000,000
PENSION AND OTHER POSTRETIREMENT BENEFITS	(684,000)	(684,000)
OTHER NON-CURRENT LIABILITIES	41,620,000	33,698,000
INTERCOMPANY PAYABLE	318,676,000	318,676,000
TOTAL RAYONIER INC. SHAREHOLDERS’ EQUITY	2,822,945,000	2,814,408,000
Noncontrolling interest	104,400,000	99,917,000
TOTAL SHAREHOLDERS’ EQUITY	2,927,345,000	2,914,325,000
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 3,360,305,000	$ 3,355,773,000