Long-Lived Assets (Tables)

6 Months Ended

Jun. 30, 2017

Long-Lived Assets

Schedule of property, plant and equipment

Property, plant and equipment consisted of the following (dollars in thousands):

	June 30,		December 31,
	2017		2016
Property, plant and equipment cost	$	1,081,757	$	1,036,137
Less accumulated depreciation		(480,425)		(440,140)
	$	601,332	$	595,997

Schedule of identifiable intangible assets

The gross carrying amount and accumulated amortization of identifiable intangible assets are as follows (dollars in thousands):

	June 30, 2017						December 31, 2016
	Gross				Net		Gross				Net
	Carrying		Accumulated		Carrying		Carrying		Accumulated		Carrying
	Value		Amortization		Value		Value		Amortization		Value
Subject to amortization:
Customer relationships	$	21,709	$	17,141	$	4,568	$	21,709	$	16,299	$	5,410
Trade name and other		320		311		9		320		302		18
		22,029		17,452		4,577		22,029		16,601		5,428
Not subject to amortization:
Brand name		27,300		—		27,300		27,300		—		27,300
		27,300		—		27,300		27,300		—		27,300
	$	49,329	$	17,452	$	31,877	$	49,329	$	16,601	$	32,728

Schedule of estimated amortization expense

Amortization expense amounted to $0.9 million and $1.1 million for the six months ended June 30, 2017 and 2016, respectively.  Estimated amortization expense for the next five years and thereafter is as follows (dollars in thousands):

Year ended December 31,
2017 (remaining months)	$	852
2018		1,307
2019		930
2020		574
2021		270
Thereafter		644
	$	4,577