Commitments And Contingencies (Narrative) (Details) $ / shares in Units, $ in Thousands	1 Months Ended			6 Months Ended			12 Months Ended			114 Months Ended
	Mar. 31, 2018 $ / shares shares	Sep. 30, 2017 USD ($) item	Oct. 31, 2013 USD ($)	Jun. 30, 2018 USD ($) store item	Jun. 30, 2017 USD ($)		Dec. 31, 2017 USD ($)		Dec. 31, 2015	Jun. 30, 2017 USD ($)
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Payments to subsidies				$ 600	$ 100
Accrued liabilities and other				$ 86,009			$ 77,317	[1]
Number of HOAs, subsidies provided to | item				10
Period of purchase of completed VOI inventory				5 years
Inventory purchased				$ 25,770	$ 26,351	[1]
Number of opt-ins | item		80		59
Average annual default rates				8.40%					6.90%
Percent of total delinquencies subject to letters				15.40%
Accrued liabilities				$ 2,100
Purchase period, from lawsuit				6 years
Period which plaintiffs received calls				12 months
Stock Appreciation Rights (SARs) [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Awards vesting period				5 years
Performance Units [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Period of awards right to receive cash payment				2 years
Purchase Commitment [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Inventory purchased				$ 4,600
Total purchase commitment			$ 35,100
Implemented Initiative, Streamline Operations In Certain Areas, Facilitate Future Growth [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Severance expense							5,800
Amount of future payment				600
Subsidies To Certain HOAs [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Accrued liabilities and other				$ 4,600			$ 0
Executive Officers [Member] | Stock Appreciation Rights (SARs) [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Percent of awards granted				30.00%
Executive Officers [Member] | Performance Units [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Percent of awards granted				70.00%
Senior Vice Presidents [Member] | Performance Units [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Percent of awards granted				100.00%
Executive [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Amount of future payment		$ 2,900		$ 1,600
Officers [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Approved for grants | shares	639,643
Approved for grants, exercise price | $ / shares	$ 19.72
Bass Pro [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Number of stores vacation packages are sold | store				68
Compensation paid under agreement on sales				$ 0
Percent of volume sales from agreement				14.00%	15.00%
Aggregate amount of purchaser default adjustments										$ 4,800

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