Long-Term Investments (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Summary of Available-for-Sale Securities

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

December 31, 2016	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Failed Auction Security	$	3,000	$	—	$	492	$	2,508
December 31, 2015	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Failed Auction Security	$	3,000	$	—	$	474	$	2,526
Brokered certificates of deposit		340		—		—		340
	$	3,340	$	—	$	474	$	2,866

Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities

The amortized cost and estimated fair value of available-for-sale securities on December 31, 2016, by contractual maturities, are shown below (in thousands):

	Cost		Estimated Fair Value
Due in twenty to forty years	$	3,000	$	2,508

Rollforward of Credit (Gain) Loss Recognized in Earnings on Available-for-Sale Auction Rate Securities

The following table represents a rollforward of the activity related to the credit loss recognized in earnings on available-for-sale auction rate securities held by the Company for the years ended December 31 (in thousands):

	2016			2015			2014
Balance at the beginning of the period	$	72		$	84		$	395
Reductions in the amount related to credit gain for which other-than-temporary impairment was not previously recognized		(13	)		(12	)		(39	)
Reductions for securities sold during the period		—			—			(272	)
Balance at the end of the period	$	59		$	72		$	84