Lines of Credit and Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Instruments [Abstract]

Schedule of Total Debt Instruments

At December 31, 2016 and December 31, 2015, total long-term debt, net of debt issuance costs of $8.1 million and $10.6 million, respectively, consists of the following:

(in thousands)	2016		2015
3.19% Series A Senior Notes due October 16, 2019	$	73,408	$	73,790
3.75% Series B Senior Notes due October 16, 2022	301,601		302,943
3.90% Series C Senior Notes due October 16, 2024	26,910		26,898
0.375% Senior Unsecured Cash Convertible Notes due 2019	402,806		391,111
0.875% Senior Unsecured Cash Convertible Notes due 2021	262,371		254,284
Total long-term debt	$	1,067,096	$	1,049,026

Schedule of Maturities of Long-term Debt

of long-term debt as of December 31, 2016 are as follows:

Year ending December 31,	(in thousands)
2017	$	—
2018	—
2019	476,214
2020	—
2021	262,371
thereafter	328,511
	$	1,067,096

Schedule of Debt Conversions

Interest expense related to the Cash Convertible Notes was comprised of the following:

	Year-Ended December 31
(in thousands)	2016		2015
Coupon interest	$	4,238	$	4,238
Amortization of original issuance discount	17,503		16,935
Amortization of debt issuance costs	2,279		2,220
Total interest expense related to the Cash Convertible Notes	$	24,020	$	23,393