Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]

The following tables categorize items measured at fair value at December 31, 2016 and 2015:

			Fair Value Measurement at Reporting Date Using
			Quoted Prices		Significant Other		Significant
			in Active Markets		Observable		Unobservable
			for Identical Assets		Inputs		Inputs
December 31, 2016			(Level 1)		(Level 2)		(Level 3)
(Dollars in thousands)
Assets
Certificates of deposit	$	750	$	—	$	750	$	—
Cash surrender value	7,480		—		7,480		—
Derivative contracts	13		—		13		—
Total	8,243		—		8,243		—
Liabilities
Derivative contracts	24,773		—		24,773		—
Total	$	24,773	$	—	$	24,773	$	—

			Fair Value Measurement at Reporting Date Using
			Quoted Prices		Significant Other		Significant
			in Active Markets		Observable		Unobservable
			for Identical Assets		Inputs		Inputs
December 31, 2015			(Level 1)		(Level 2)		(Level 3)
(Dollars in thousands)
Assets
Certificates of deposit	$	950	$	—	$	950	$	—
Cash surrender value	6,923		—		6,923		—
Derivative contracts	113		—		113		—
Total	7,986		—		7,986		—
Liabilities
Derivative contracts	14,159		—		14,159		—
Total	$	14,159	$	—	$	14,159	$	—