Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2017

Long-Term Debt [Abstract]

Schedule of long-term debt instruments

Long-term debt consists of the following:

	December 31, 2017			December 31, 2016
Credit facility	$	150,000		$	143,000
Convertible senior debentures, due 2040		110,412			108,120
Convertible senior debentures, due 2041		56,641			55,442
Convertible senior debentures, due 2042		62,518			61,341
Deferred financing costs		(9,101	)		(10,880	)
		370,470			357,023
Less current portion		-			-
	$	370,470		$	357,023

Key terms of the convertible debentures

The following table summarizes some key facts and terms regarding the three series of outstanding convertible senior debentures following the adjustment made to the conversion rate of the debentures on the ex-dividend date of the December 21, 2017 dividend payment:

	Due 2040			Due 2041			Due 2042
Issuance date	November 9, 2010			May 13, 2011			May 31, 2012
Maturity date	November 15, 2040			May 15, 2041			June 1, 2042
Principal amount	$	275,000		$	150,000		$	150,000
Cash coupon rate (per annum)		2.25	%		2.25	%		2.25	%
Nonconvertible debt borrowing rate at issuance (per annum)		8.00	%		8.375	%		7.50	%
Conversion rate effective December 6, 2017 (per $1 principal amount)		77.2085			56.3427			90.7787
Effective conversion price effective December 6, 2017 (per share)	$	12.95		$	17.75		$	11.02
130% of the conversion price (per share)	$	16.84		$	23.08		$	14.33
Call date	November 20, 2020			May 20, 2021			June 7, 2022

Liability and equity components of the convertible debentures

The carrying values of the liability and equity components of the convertible debentures are reflected in the Company's accompanying consolidated balance sheets as follows:

	Principal amount of the debentures		Unamortized discount			Embedded derivative		Carrying value of liability component		Equity component (including temporary equity) - net carrying value
December 31, 2017
Due 2040	$	275,000		(164,794	)		206	$	110,412	$	110,094
Due 2041	$	150,000		(93,573	)		214	$	56,641	$	62,246
Due 2042	$	150,000		(87,600	)		118	$	62,518	$	57,874
Total	$	575,000	$	(345,967	)	$	538	$	229,571	$	230,214
December 31, 2016
Due 2040	$	275,000		(167,273	)		393	$	108,120	$	110,094
Due 2041	$	150,000		(94,843	)		285	$	55,442	$	62,246
Due 2042	$	150,000		(88,835	)		176	$	61,341	$	57,874
Total	$	575,000	$	(350,951	)	$	854	$	224,903	$	230,214

Schedule of Interest Expense on Convertible Debt [Table Text Block]

Interest expense related to the debentures is reflected on the accompanying consolidated statements of operations for the years ended December 31:

	Contractual coupon interest		Non-cash amortization of debt discount		Non-cash amortization of deferred financing costs		Non-cash change in value of derivative liability			Total interest expense related to the debentures
2017
Due 2040	$	6,188		2,479		88		(187	)	$	8,568
Due 2041	$	3,375		1,270		47		(71	)	$	4,621
Due 2042	$	3,375		1,235		54		(58	)	$	4,606
Total	$	12,938	$	4,984	$	189	$	(316	)	$	17,795
2016
Due 2040	$	6,188		2,292		88		(183	)	$	8,385
Due 2041	$	3,375		1,171		47		(153	)	$	4,440
Due 2042	$	3,375		1,147		54		(126	)	$	4,450
Total	$	12,938	$	4,610	$	189	$	(462	)	$	17,275
2015
Due 2040	$	6,188		2,120		88		50		$	8,446
Due 2041	$	3,375		1,078		47		97		$	4,597
Due 2042	$	3,375		1,066		54		64		$	4,559
Total	$	12,938	$	4,264	$	189	$	211		$	17,602

Aggregate annual maturities of long-term debt

Other Borrowings Information

Aggregate annual maturities of long-term debt, based on the terms stated in the respective agreements, are as follows:

2018	$	-
2019		-
2020		150,000
2021		-
2022		-
Thereafter		575,000