CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
BALANCES at Dec. 31, 2012	$ 268,727	$ 702	$ 618,550	$ (323,657)	$ 248	$ (27,116)
BALANCES (in shares) at Dec. 31, 2012		68,378,984
Net income for the year	46,529	$ 0	0	46,529	0	0
Foreign currency translation	(266)	0	0	0	(266)	0
Stock-based compensation	6,822	$ 0	6,822	0	0	0
Stock-based compensation (in shares)		62,183
Stock repurchase	(35)	$ 0	0	0	0	(35)
Stock repurchase (in shares)		(3,665)
Common stock issued in connection with: Stock option exercises	602	$ 3	599	0	0	0
Common stock issued in connection with: Stock option exercises (in shares)		85,917
BALANCES at Dec. 31, 2013	322,379	$ 705	625,971	(277,128)	(18)	(27,151)
BALANCES (in shares) at Dec. 31, 2013		68,523,419
Net income for the year	60,930	$ 0	0	60,930	0	0
Foreign currency translation	(619)	0	0	0	(619)	0
Stock-based compensation	7,718	$ 4	7,714	0	0	0
Stock-based compensation (in shares)		392,470
Stock repurchase	(1,497)	$ 0	0	0	0	(1,497)
Stock repurchase (in shares)		(113,203)
Common stock issued in connection with: Stock option exercises	1,921	$ 0	1,921	0	0	0
Common stock issued in connection with: Stock option exercises (in shares)		195,383
BALANCES at Dec. 31, 2014	390,832	$ 709	635,606	(216,198)	(637)	(28,648)
BALANCES (in shares) at Dec. 31, 2014		68,998,069
Net income for the year	104,289	$ 0	0	104,291	0	0
Foreign currency translation	(863)	0	0	0	(863)	0
Stock-based compensation	10,010	$ 4	10,006	0	0	0
Stock-based compensation (in shares)		396,389
Stock repurchase	(61,757)	$ 0	0	$ 0	$ 0	$ (61,757)
Stock repurchase (in shares)		(4,651,570)
Equity component of convertible senior notes repurchase	(4,714)	$ 0	(4,714)
Common stock issued in connection with: Stock option exercises	2,012	$ 2	2,010	$ 0	$ 0	$ 0
Common stock issued in connection with: Stock option exercises (in shares)		186,622
BALANCES at Dec. 31, 2015	$ 439,811	$ 715	$ 642,908	$ (111,907)	$ (1,500)	$ (90,405)
BALANCES (in shares) at Dec. 31, 2015		64,929,510

Adjustment to additional paid in capital resulting from the recognition of convertible debt instruments as two separate components - a debt component and an equity component. This bifurcation may result in a basis difference associated with the liability component that represents a temporary difference for purposes of applying accounting for income taxes. The initial recognition of deferred taxes for the tax effect of that temporary difference is as an adjustment to additional paid in capital.

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