CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Shares	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Sub-Total	Treasury Stock
Balance at Dec. 31, 2010	$ 342,964	$ 590	$ 169,284	$ 208,015	$ (4,074)	$ 373,815	$ (30,851)
Balance (in shares) at Dec. 31, 2010		58,989,578					3,070,720
Increase (Decrease) in Shareholders' Equity
Net income	39,224			39,224		39,224
Other comprehensive income (loss), net of tax (Note 14)	(9,443)				(9,443)	(9,443)
Employee and director stock plans	4,794	4	4,790			4,794
Employee and director stock plans (in shares)		392,058
Treasury stock purchased	(422)						(422)
Treasury stock purchased (in shares)							29,699
Balance at Dec. 31, 2011	377,117	594	174,074	247,239	(13,517)	408,390	(31,273)
Balance (in shares) at Dec. 31, 2011		59,381,636					3,100,419
Increase (Decrease) in Shareholders' Equity
Net income	23,272			23,272		23,272
Other comprehensive income (loss), net of tax (Note 14)	(3,010)				(3,010)	(3,010)
Employee and director stock plans	4,495	3	4,492			4,495
Employee and director stock plans (in shares)		344,998
Accelerated share repurchase (Note 10)	(50,000)	(33)	(9,967)			(10,000)	(40,000)
Accelerated share repurchase (Note 10) (in shares)		(3,276,002)					3,276,002
Treasury stock purchased	(577)						(577)
Treasury stock purchased (in shares)							38,755
Balance at Dec. 31, 2012	351,297	564	168,599	270,511	(16,527)	423,147	(71,850)
Balance (in shares) at Dec. 31, 2012		56,450,632					6,415,176
Increase (Decrease) in Shareholders' Equity
Net income	45,713			45,713		45,713
Other comprehensive income (loss), net of tax (Note 14)	15,387				15,387	15,387
Employee and director stock plans	7,442	4	7,438			7,442
Employee and director stock plans (in shares)		441,084
Accelerated share repurchase (Note 10)		4	(5,717)			(5,713)	5,713
Accelerated share repurchase (Note 10) (in shares)		340,334					(340,334)
Share repurchase (Note 10)	(2,991)						(2,991)
Share repurchase (Note 10) (in shares)							146,800
Treasury stock purchased	(343)						(343)
Treasury stock purchased (in shares)							20,684
Balance at Dec. 31, 2013	$ 416,505	$ 572	$ 170,320	$ 316,224	$ (1,140)	$ 485,976	$ (69,471)
Balance (in shares) at Dec. 31, 2013		57,232,050					6,242,326