Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2017

Long-term Debt and Capital Lease Obligations [Abstract]

Schedule of Long-Term Debt

Long-term debt, principally to banks and bondholders, consists of:

(in thousands, except interest rates)	June 30, 2017	December 31, 2016
Private placement with a fixed interest rate of 6.84%, due 2017	$50,000	$50,000
Revolving credit agreement with borrowings outstanding at an end of period interest rate of 2.70% in 2017 and 2.58% in 2016 (including the effect of interest rate hedging transactions, as described below), due in 2021	430,000	418,000
Obligation under capital lease, matures 2022	15,762	16,584
Long-term debt	495,762	484,584
Less: current portion	(51,732)	(51,666)
Long-term debt, net of current portion	$444,030	$432,918

Schedule of Future Minimum Annual Capital Lease Obilgations

The following schedule presents future minimum annual lease payments under the capital lease obligation and the present value of the minimum lease payments, as of June 30, 2017.

Years ending December 31,	(in thousands)
2017	$1,212
2018	2,473
2019	2,473
2020	2,520
2021	2,520
Thereafter	7,373
Total minimum lease payments	18,571
Less:  Amount representing interest	(2,809	)
Present value of minimum lease payments	$15,762