CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Capital Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2012	$ 434,152	$ 16,904	$ 74,272	$ 400,784	$ (57,808)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	26,234			26,234
Other comprehensive income (loss)	25,228				25,228
Stock options exercised	26,047	722	25,325
Stock issued to directors	0	15	(15)
Shares issued for employees stock purchase plan	733	25	708
Shares issued for restricted stock	(1,189)	50	(1,239)
Stock-based compensation expense	3,704		3,704
Ending Balance at Sep. 30, 2013	$ 514,909	$ 17,716	$ 102,755	$ 427,018	$ (32,580)