CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Total
Balance at Dec. 31, 2013	$ 48,421	$ 1,007,918	$ 224,575	$ (33,379)	$ 1,247,535
Net income			107,936		107,936
Other comprehensive loss				(8,239)	(8,239)
TOTAL COMPREHENSIVE INCOME					99,697
Tax effect of share-based compensation		786			786
Share-based compensation expense		18,616			18,616
Issuance of common stock, net	250	(1,379)			(1,129)
Balance at Dec. 31, 2014	48,671	1,025,941	332,511	(41,618)	1,365,505
Net income			45,292		45,292
Other comprehensive loss				(547)	(547)
TOTAL COMPREHENSIVE INCOME					44,745
Tax effect of share-based compensation		(186)			(186)
Share-based compensation expense		9,477			9,477
Issuance of common stock, net	402	284			686
Balance at Dec. 31, 2015	49,073	1,035,516	377,803	(42,165)	1,420,227
Net income			95,822		95,822
Other comprehensive loss				(3,248)	(3,248)
TOTAL COMPREHENSIVE INCOME					92,574
Tax effect of share-based compensation		(457)			(457)
Share-based compensation expense		13,423			13,423
Issuance of common stock, net	138	676			814
Convertible note proceeds allocated to conversion option, net		26,442			26,442
Balance at Dec. 31, 2016	$ 49,211	$ 1,075,600	$ 473,625	$ (45,413)	$ 1,553,023