CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss), Net [Member]
BEGINNING BALANCE at Dec. 31, 2014	$ 312,651	$ 3,300	$ 379,249	$ (65,000)	$ (71)	$ (4,827)
BEGINNING BALANCE, Shares at Dec. 31, 2014		33,137
Comprehensive income	20,755	$ 0	0	22,141	0	(1,386)
Stock based compensation expense	2,859	0	2,859	0	0	0
Common stock issued for stock based employee benefit plans	15	$ 0	17	0	(2)	0
Common stock issued for stock based employee benefit plans, shares		124
Issuance of common stock, pursuant to acquisition	17,172	$ 109	17,063	0	0	0
Issuance of common stock, pursuant to acquisition, shares		1,090
Other	1	$ 26	(26)	1	0	0
Other, shares		0
ENDING BALANCE at Dec. 31, 2015	353,453	$ 3,435	399,162	(42,858)	(73)	(6,213)
ENDING BALANCE, Shares at Dec. 31, 2015		34,351
Comprehensive income	27,902	$ 0	0	29,202	0	(1,300)
Stock based compensation expense	4,154	0	4,154	0	0	0
Common stock issued for stock based employee benefit plans	(1,161)	$ 0	2	0	(1,163)	0
Common stock issued for stock based employee benefit plans, shares		87
Common stock issued for stock options	134	$ 1	133	0	0	0
Common stock issued for stock options, shares		12
Issuance of common stock, pursuant to acquisition	50,913	$ 329	50,584	0	0	0
Issuance of common stock, pursuant to acquisition, shares		3,291
Other	2	$ 37	(34)	(1)	0	0
Other, shares		281
ENDING BALANCE at Dec. 31, 2016	435,397	$ 3,802	454,001	(13,657)	(1,236)	(7,513)
ENDING BALANCE, Shares at Dec. 31, 2016		38,022
Comprehensive income	46,868	$ 0	0	42,865	0	4,003
Reclassification of disproportionate tax effects upon adoption of new accounting pronouncement	0	0	0	706	0	(706)
Stock based compensation expense	5,267	0	5,267	0	0	0
Common stock issued for stock based employee benefit plans	(1,138)	$ 0	(15)	0	(1,123)	0
Common stock issued for stock based employee benefit plans, shares		61
Common stock issued for stock options	1,082	$ 16	1,066	0	0	0
Common stock issued for stock options, shares		91
Issuance of common stock, net of related expenses	55,641	$ 270	55,371	0	0	0
Issuance of common stock, net of related expenses, shares		2,703
Issuance of common stock, pursuant to acquisition	146,547	$ 605	145,942	0	0	0
Issuance of common stock, pursuant to acquisition, shares		6,041
ENDING BALANCE at Dec. 31, 2017	$ 689,664	$ 4,693	$ 661,632	$ 29,914	$ (2,359)	$ (4,216)
ENDING BALANCE, Shares at Dec. 31, 2017		46,918