Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning balance at Dec. 31, 2013	$ 386,623	$ 24,756	$ 307,231	$ 71,008	$ (8,118)	$ (8,254)
Beginning balance, shares at Dec. 31, 2013		24,224,151
Net income	8,136			8,136
Other comprehensive loss	4,520				4,520
Share-based compensation expense	955		955
Issuance of common stock under share-based compensation arrangements	704	70	634
Issuance of common stock under share-based compensation arrangements, Shares		70,013
Ending balance at Mar. 31, 2014	400,938	24,826	308,820	79,144	(3,598)	(8,254)
Ending balance, shares at Mar. 31, 2014		24,294,164
Beginning balance at Dec. 31, 2014	443,145	27,278	355,822	68,421	(122)	(8,254)
Beginning balance, shares at Dec. 31, 2014	26,745,529	26,745,529
Net income	13,952			13,952
Other comprehensive loss	(925)				(925)
Share-based compensation expense	1,170		1,170
Issuance of common stock under share-based compensation arrangements	609	78	531
Issuance of common stock under share-based compensation arrangements, Shares		78,510
Ending balance at Mar. 31, 2015	$ 457,951	$ 27,356	$ 357,523	$ 82,373	$ (1,047)	$ (8,254)
Ending balance, shares at Mar. 31, 2015	26,824,039	26,824,039