Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value of Financial Instruments

Schedule of fair value of the financial assets and liabilities

In accordance with the fair value hierarchy described above, the following tables show the fair value of the Company's financial assets and liabilities that are required to be measured at fair value, in thousands of dollars:

	Fair Value Measurements at December 31, 2017
	Total Carrying Value at December 31, 2017		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	$	100,304	$	100,304	$	—	$	—
Marketable securities		39,736		2,118		37,618		—
Corporate debt securities		132,477		448		132,029
Government debt securities		1,161		—		1,161
Marketable securities—restricted (SERP)		335		—		335		—
Total assets at fair value	$	274,013	$	102,870	$	171,143	$	—

	Fair Value Measurements at December 31, 2016
	Total Carrying Value at December 31, 2016		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	$	66,398	$	66,398	$	—	$	—
Marketable securities		23,723		656		23,067		—
Corporate debt securities		74,343		1,717		72,626
Government debt securities		1,067				1,067
Marketable securities—restricted (SERP)		275		—		275		—
Total assets at fair value	$	165,806	$	68,771	$	97,035	$	—
Liabilities:
Derivative liabilities	$	114	$	—	$	—	$	114

Schedule of unrestricted marketable securities

Unrestricted marketable securities held by the Company were as follows, in thousands of dollars:

At December 31, 2017:

Available for Sale	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate and government debt securities	$	174,235		48		(909	)	$	173,374

At December 31, 2016:

Available for Sale	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Corporate and government debt securities	$	99,487		86		(440	)	$	99,133

Schedule of contractual maturities of the unrestricted available for sale marketable securities held

The contractual maturities of the unrestricted available for sale marketable securities held by the Company were as follows, in thousands of dollars:

	December 31, 2017
Less Than 1 Year	$	39,736
1 year to 2 years		42,921
2 year to 3 years		43,021
3 years to 4 years		47,696
Greater Than 4 Years		—
Total	$	173,374