Segment Reporting (Details) $ in Thousands		3 Months Ended			12 Months Ended
		Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)		Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Total revenues		$ 167,522	$ 162,567	[1]
Cost of VOIs sold		1,812	3,159	[1]	$ 17,679	$ 28,829
Cost of other fee-based services		17,411	16,107	[1]
Cost reimbursements		16,200	14,670	[1]	52,639	49,557
Selling, general and administrative expenses		93,549	89,835	[1]	421,199	419,929
Interest expense		7,767	7,644	[1]
Other expense, net	[1]		245
Total costs and expenses		136,739	131,660	[1]
Income before non-controlling interest and provision for income taxes		30,783	30,907	[1]	$ 136,998	129,624
Add: Depreciation and amortization		$ 3,946	3,422	[1]
Number of reportable segments | segment		2			2
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Total revenues		$ 1,713	2,189
Selling, general and administrative expenses		21,592	15,499
Interest expense		3,056	3,338
Other expense, net			245
Total costs and expenses		24,648	19,082
Income before non-controlling interest and provision for income taxes		(22,935)	(16,893)
Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues		(1,445)	(1,161)
Net carrying cost of VOI inventory		(2,517)	(1,674)
Cost of other fee-based services		2,517	1,674
Selling, general and administrative expenses		141	330
Mortgage servicing expense		(1,586)	(1,491)
Total costs and expenses		(1,445)	(1,161)
Sales Of VOIs And Financing [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		125,719	123,565
Cost of VOIs sold		1,812	3,159
Net carrying cost of VOI inventory		2,517	1,674
Cost of other fee-based services		1,242	1,286
Selling, general and administrative expenses		71,816	74,006
Mortgage servicing expense		1,586	1,491
Interest expense		4,711	4,306
Total costs and expenses		83,684	85,922
Income before non-controlling interest and provision for income taxes		42,035	37,643
Add: Depreciation and amortization		1,667	1,518
Segment Adjusted EBITDA	[2]	43,702	39,161
Resort Operations And Club Management [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		41,535	37,974
Cost of other fee-based services		13,652	13,147
Cost reimbursements		16,200	14,670
Total costs and expenses		29,852	27,817
Income before non-controlling interest and provision for income taxes		11,683	10,157
Add: Depreciation and amortization		395	405
Segment Adjusted EBITDA	[2]	12,078	10,562
Sales of VOIs [Member]
Segment Reporting Information [Line Items]
Total revenues		56,141	54,236	[1]	$ 242,017	273,874
Sales of VOIs [Member] | Sales Of VOIs And Financing [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		56,141	54,236
Fee-Based Sales Commission Revenue [Member]
Segment Reporting Information [Line Items]
Total revenues		45,854	45,154	[1]
Fee-Based Sales Commission Revenue [Member] | Sales Of VOIs And Financing [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		45,854	45,154
Other Fee-Based Services Revenue [Member]
Segment Reporting Information [Line Items]
Total revenues		28,024	26,121	[1]
Other Fee-Based Services Revenue [Member] | Sales Of VOIs And Financing [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		2,689	2,817
Other Fee-Based Services Revenue [Member] | Resort Operations And Club Management [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		25,335	23,304
Cost Reimbursements [Member]
Segment Reporting Information [Line Items]
Total revenues		16,200	14,670	[1]	$ 52,639	$ 49,557
Cost Reimbursements [Member] | Resort Operations And Club Management [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		16,200	14,670
Mortgage Servicing Revenue [Member] | Eliminations [Member]
Segment Reporting Information [Line Items]
Total revenues		(1,445)	(1,161)
Mortgage Servicing Revenue [Member] | Sales Of VOIs And Financing [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		1,445	1,161
Interest Income [Member]
Segment Reporting Information [Line Items]
Total revenues		21,122	22,386	[1]
Interest Income [Member] | Corporate And Other [Member]
Segment Reporting Information [Line Items]
Total revenues		1,532	2,189
Interest Income [Member] | Sales Of VOIs And Financing [Member] | Reportable Segments [Member]
Segment Reporting Information [Line Items]
Total revenues		19,590	$ 20,197
Other Income, Net [Member]
Segment Reporting Information [Line Items]
Total revenues		181
Other Income, Net [Member] | Corporate And Other [Member]
Segment Reporting Information [Line Items]
Total revenues		$ 181

[1] * See Note 2 for summary of adjustments.

[2] See Management's Discussion and Analysis of Financial Condition and Results of Operations for information regarding Adjusted EBITDA, including, how we define Adjusted EBITDA and a reconciliation of Adjusted EBITDA to net income.