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, 2015	$ 242,567	$ 26	$ 124,834	$ 181,539	$ (63,832)
Beginning balance (in shares) at Dec. 31, 2015		25,773
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and vesting of restricted stock	2,893		2,893
Stock-based compensation and vesting of restricted stock (in shares)		74
Net income	25,140			25,140
Conversion of convertible debt	45,286	$ 1	45,285
Conversion of convertible debt (in shares)		1,536
Dividends declared	(15,571)			(15,571)
Change in fair value of derivative financial instrument, net of tax	(506)				(506)
Minimum pension adjustment, net of tax	139				139
Cumulative foreign currency translation adjustment	(11,887)				(11,887)
Repurchases of common stock	(4,713)		(4,713)
Repurchases of common stock (in shares)		(177)
Ending balance at Dec. 31, 2016	283,348	$ 27	168,299	191,108	(76,086)
Ending balance (in shares) at Dec. 31, 2016		27,206
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and vesting of restricted stock	3,186		3,186
Stock-based compensation and vesting of restricted stock (in shares)		104
Net income	51,427			51,427
Conversion of convertible debt	51,853	$ 2	51,851
Conversion of convertible debt (in shares)		1,748
Dividends declared	(19,331)			(19,331)
Change in fair value of derivative financial instrument, net of tax	194				194
Minimum pension adjustment, net of tax	1,990				1,990
Cumulative foreign currency translation adjustment	24,038				24,038
Ending balance at Dec. 31, 2017	396,705	$ 29	223,336	223,204	(49,864)
Ending balance (in shares) at Dec. 31, 2017		29,058
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation and vesting of restricted stock	5,094		5,094
Net income	35,341			35,341
Common stock and restricted stock issued in A&S acquisition	1,458,726	$ 35	1,458,691
Common stock and restricted stock issued in A&S acquisition, (in shares)		35,128
Dividends declared	(25,941)			(25,941)
Change in fair value of derivative financial instrument, net of tax	(12,490)				(12,490)
Minimum pension adjustment, net of tax	3,481				3,481
Cumulative foreign currency translation adjustment	(12,720)				(12,720)
Ending balance at Dec. 31, 2018	$ 1,848,196	$ 64	$ 1,687,121	$ 232,604	$ (71,593)
Ending balance (in shares) at Dec. 31, 2018		64,186