Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2016	$ 283,348	$ 27	$ 168,299	$ 191,108	$ (76,086)
Beginning balance (in shares) at Dec. 31, 2016		27,206
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and vesting of restricted stock	2,457		2,457
Stock-based compensation and vesting of restricted stock (in shares)		100
Net income	38,987			38,987
Conversion of convertible debt	51,851	$ 2	51,849
Conversion of Convertible Debt (in shares)		1,748
Dividends declared	(14,329)			(14,329)
Change in fair value of Derivative Financial Instruments, net of tax	326
Cumulative foreign currency translation adjustment	21,157
Changes in Accumulated Other Comprehensive Income	21,251				21,251
Ending balance at Sep. 30, 2017	383,565	$ 29	222,605	215,766	(54,835)
Ending balance (in shares) at Sep. 30, 2017		29,054
Beginning balance at Jun. 30, 2017	368,779	$ 29	222,913	207,439	(61,602)
Beginning balance (in shares) at Jun. 30, 2017		28,996
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and vesting of restricted stock	(308)		(308)
Stock-based compensation and vesting of restricted stock (in shares)		58
Net income	13,277			13,277
Dividends declared	(4,950)			(4,950)
Change in fair value of Derivative Financial Instruments, net of tax	(331)
Cumulative foreign currency translation adjustment	6,673
Changes in Accumulated Other Comprehensive Income	6,767				6,767
Ending balance at Sep. 30, 2017	383,565	$ 29	222,605	215,766	(54,835)
Ending balance (in shares) at Sep. 30, 2017		29,054
Beginning balance at Dec. 31, 2017	396,705	$ 29	223,336	223,204	(49,864)
Beginning balance (in shares) at Dec. 31, 2017		29,058
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and vesting of restricted stock	980		980
Stock-based compensation and vesting of restricted stock (in shares)		110
Net income	40,321			40,321
Dividends declared	(14,991)			(14,991)
Change in fair value of Derivative Financial Instruments, net of tax	923				923
Minimum Pension adjustment, net of tax	4,392				4,392
Cumulative foreign currency translation adjustment	(11,170)				(11,170)
Ending balance at Sep. 30, 2018	417,160	$ 29	224,316	248,534	(55,719)
Ending balance (in shares) at Sep. 30, 2018		29,168
Beginning balance at Jun. 30, 2018	412,892	$ 29	224,526	241,249	(52,912)
Beginning balance (in shares) at Jun. 30, 2018		29,108
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and vesting of restricted stock	(210)		(210)
Stock-based compensation and vesting of restricted stock (in shares)		60
Net income	12,313			12,313
Dividends declared	(5,028)			(5,028)
Change in fair value of Derivative Financial Instruments, net of tax	(155)				(155)
Cumulative foreign currency translation adjustment	(2,652)				(2,652)
Ending balance at Sep. 30, 2018	$ 417,160	$ 29	$ 224,316	$ 248,534	$ (55,719)
Ending balance (in shares) at Sep. 30, 2018		29,168

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Adjustment to additional paid in capital resulting from the recognition of convertible debt instruments as two separate components - a debt component and an equity component. This bifurcation may result in a basis difference associated with the liability component that represents a temporary difference for purposes of applying accounting for income taxes. The initial recognition of deferred taxes for the tax effect of that temporary difference is as an adjustment to additional paid in capital.

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Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Number of shares issued during the period as a result of the conversion of convertible securities.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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