Long-Term Investments (Tables)

9 Months Ended

Sep. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Summary of Available-for-Sale Securities

The following is a summary of available-for-sale securities (in thousands):

September 30, 2017	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Failed Auction Security	$	3,000	$	—	$	401	$	2,599
December 31, 2016	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Failed Auction Security	$	3,000	$	—	$	492	$	2,508

Rollforward of Credit (Gain) Loss Recognized in Earnings on Failed Auction Security

The following table represents a rollforward of the activity related to the credit loss recognized in earnings on the Failed Auction Security for the nine months ended September 30 (in thousands):

	2017			2016
Balance at the beginning of the period	$	59		$	72
Reductions in the amount related to credit gain for which other-than-temporary impairment was not previously recognized		(9	)		(10	)
Balance at the end of the period	$	50		$	62