CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings (Accumulated Deficit)	Treasury Stock	Accumulated Other Comprehensive Income (Loss), Net
Beginning balance (in shares) at Dec. 31, 2016		38,022
Beginning balance at Dec. 31, 2016	$ 435,397	$ 3,802	$ 454,001	$ (13,657)	$ (1,236)	$ (7,513)
Comprehensive income	46,868			42,865		4,003
Reclassification of disproportionate tax effects upon adoption of new accounting pronouncement	0			706		(706)
Stock based compensation expense	5,267		5,267
Common stock issued for stock based employee benefit plans (in shares)		61
Common stock issued for stock based employee benefit plans	(1,138)		(15)		(1,123)
Common stock issued for stock options (in shares)		91
Common stock issued for stock options	1,082	$ 16	1,066
Issuance of common stock, net of related expenses (in shares)		2,703
Issuance of common stock, net of related expenses	55,641	$ 270	55,371
Issuance of common stock, pursuant to acquisition (in shares)		6,041
Issuance of common stock, pursuant to acquisition	146,547	$ 605	145,942
Ending balance (in shares) at Dec. 31, 2017		46,918
Ending balance at Dec. 31, 2017	689,664	$ 4,693	661,632	29,914	(2,359)	(4,216)
Comprehensive income	58,316			67,275		(8,959)
Stock based compensation expense (in shares)		32
Stock based compensation expense	7,823		7,823
Common stock issued for stock based employee benefit plans (in shares)		43
Common stock issued for stock based employee benefit plans	(1,031)		(6)		(1,025)
Common stock issued for stock options (in shares)		368
Common stock issued for stock options	2,009	$ 43	1,966
Issuance of common stock, pursuant to acquisition (in shares)		4,000
Issuance of common stock, pursuant to acquisition	107,486	$ 400	107,086
Ending balance (in shares) at Dec. 31, 2018		51,361
Ending balance at Dec. 31, 2018	864,267	$ 5,136	778,501	97,074	(3,384)	(13,060)
Comprehensive income	116,264			98,739		17,525
Stock based compensation expense (in shares)		30
Stock based compensation expense	7,244		7,244
Common stock issued for stock based employee benefit plans (in shares)		94
Common stock issued for stock based employee benefit plans	(2,668)	$ 12	(32)		(2,648)
Common stock issued for stock options (in shares)		29
Common stock issued for stock options	428	$ 3	425
Other	104		104
Ending balance (in shares) at Dec. 31, 2019		51,514
Ending balance at Dec. 31, 2019	$ 985,639	$ 5,151	$ 786,242	$ 195,813	$ (6,032)	$ 4,465