Long-Term Debt (Tables)

6 Months Ended

Jun. 30, 2020

Debt Disclosure [Abstract]

Summary of Long-term Debt

The following table summarizes the Company’s long-term debt.

	June 30,			December 31,
	2020			2019
4.25% Convertible senior notes, due March 1, 2037	$	139,200		$	143,750
3.95% Promissory note, due through February 17, 2020		—			8,881
4% Promissory note, due through February 1, 2031		7,081			7,345
3.75% Callable promissory note, due through September 1, 2036		7,783			7,955
4.55% Promissory note, due through August 1, 2036		5,588			5,704
3.90% Promissory note, due through April 1, 2032		9,945			—
Finance lease liabilities, due through August 15, 2023		52			60
Total principal amount		169,649			173,695
Less: unamortized discount and issuance costs		(7,810	)		(10,000	)
Total long-term debt	$	161,839		$	163,695

Summary of Future Maturities of Long-Term Debt

The following table summarizes future maturities of long-term debt as of June 30, 2020, which takes into consideration the assumption that the 4.25% Convertible Senior Notes are repurchased at the earliest call date.

Due in 12 months following June 30,
2020	$	1,494
2021		140,755
2022		1,612
2023		1,668
2024		1,733
Thereafter		22,387
Total	$	169,649

Schedule of Interest Expense Related to Long-Term Debt

Information with respect to interest expense related to long-term debt is as follows:

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2020			2019			2020			2019
Interest Expense:
Contractual interest	$	1,832		$	1,837		$	3,638		$	4,394
Non-cash expense (a)		1,068			999			2,120			2,789
Capitalized interest (b)		(42	)		(79	)		(83	)		(158	)
	$	2,858		$	2,757		$	5,675		$	7,025

(a) Includes amortization of debt discount and issuance costs.

(b) Interest was capitalized for a construction project.