Long-Term Investments (Tables)

3 Months Ended

Mar. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Summary of Available-for-Sale Securities

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

March 31, 2019	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Failed Auction Security	$	3,000	$	—	$	454	$	2,546

December 31, 2018	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Failed Auction Security	$	3,000	$	—	$	474	$	2,526

Cost and Estimated Fair Value of Failed Auction Security by Contractual Maturities

The cost and estimated fair value of the Failed Auction Security on March 31, 2019, by contractual maturity,  are shown below (in thousands):

	Cost		Estimated Fair Value
Due in twenty to forty years	$	3,000	$	2,546

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 three months ended March 31 (in thousands):

	2019			2018
Balance at the beginning of the period	$	41		$	48
Reductions in the amount related to credit gain for which other-than-temporary impairment was not previously recognized		(1	)		(2	)
Balance at the end of the period	$	40		$	46