Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2018

Debt Instrument [Line Items]

Summary of Long-Term Debt

We had the following outstanding letters of credit at December 31, 2018 (dollars in thousands):

SemGroup $1.0 billion revolving credit facility	2.75%	$	24,335
Secured bi-lateral (1)	1.75%	$	19,053

(1) Secured bi-lateral letters of credit are external to the SemGroup $1.0 billion revolving credit facility and do not reduce availability for borrowing on the credit facility.Our long-term debt consisted of the following (dollars in thousands):

	Interest rate at December 31, 2018	December 31, 2018			December 31, 2017
Senior unsecured notes due 2022	5.625%	400,000			400,000
Senior unsecured notes due 2023	5.625%	350,000			350,000
Senior unsecured notes due 2025	6.375%	325,000			325,000
Senior unsecured notes due 2026	7.250%	300,000			300,000
SemGroup $1.0 billion corporate revolving credit facility (1)
Alternate base rate borrowings	7.250%	24,500			—
Eurodollar borrowings	5.156%	95,000			131,000
HFOTCO acquisition final payment		—			565,868
HFOTCO term loan B (2)	5.280%	597,000			532,125
HFOTCO tax exempt notes payable due 2050	3.399%	225,000			225,000
HFOTCO $75 million revolving credit facility		—			60,000
Capital leases		—			25
Unamortized premium (discount) and debt issuance costs, net		(31,666		)	(30,398		)
Total long-term debt, net		2,284,834			2,858,620
Less: current portion of long-term debt		6,000			5,525
Noncurrent portion of long-term debt, net		$	2,278,834		$	2,853,095

(1) SemGroup $1.0 billion corporate revolving credit facility matures on May 15, 2021.

(2) HFOTCO term loan B is due in quarterly installments of $1.5 million, with a final payment due on June 26, 2025.

Early Redemption Premium Percentages [Table Text Block]

Except as described below, the Company may redeem the Notes, in whole or in part, at the redemption prices (expressed as percentages of principal amount) set forth below, plus accrued and unpaid interest, if redeemed during the twelve-month period beginning with each period as indicated below:

2022 Notes
From and after July 15, 2018	102.813%
From and after July 15, 2019	101.406%
From and after July 15, 2020	100.000%

2023 Notes
Not redeemable before May 15, 2019
From and after May 15, 2019	102.813%
From and after May 15, 2020	101.406%
From and after May 15, 2021	100.000%

2025 Notes
Not redeemable before March 15, 2020
From and after March 15, 2020	103.188%
From and after March 15, 2021	101.594%
From and after March 15, 2022	100.000%

2026 Notes
Not redeemable before March 15, 2021
From and after March 15, 2021	103.625%
From and after March 15, 2022	101.813%
From and after March 15, 2023	100.000%

Scheduled Principal Payments of Debt

The following table summarizes the scheduled principal payments as of December 31, 2018 (in thousands):

	Total
For the year ended:
December 31, 2019	$	6,000
December 31, 2020	6,000
December 31, 2021	125,500
December 31, 2022	406,000
December 31, 2023	356,000
Thereafter	1,417,000
Total	$	2,316,500