Consolidated Statements of Changes in Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands		Common Stock [Member]	Additional Paid-in Capital [Member]	AOCI Attributable to Parent [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2013		54,604
Balance at Dec. 31, 2013		$ 546	$ 254,188		$ 441,417	$ 696,151
Issuance of restricted shares, net of forfeitures (in shares)		723
Issuance of restricted shares, net of forfeitures		$ 7	(7)
Employee tax withholding on restricted shares vesting (in shares)		(153)
Employee tax withholding on restricted shares vesting		$ (2)	(4,376)			(4,378)
Issuance of common shares for stock options exercised (in shares)		159
Issuance of common shares for stock options exercised		$ 2	831			833
Tax effect of share-based compensation			2,118			2,118
Share-based compensation			18,350			18,350
Net income (loss)					68,823	68,823
Foreign currency translation gain (loss)				$ (45)		(45)
Balance (in shares) at Dec. 31, 2014		55,333
Balance at Dec. 31, 2014		$ 553	271,104	(45)	510,240	781,852
Issuance of restricted shares, net of forfeitures (in shares)		2,719
Issuance of restricted shares, net of forfeitures		$ 27	3,006			3,033
Employee tax withholding on restricted shares vesting (in shares)		(215)
Employee tax withholding on restricted shares vesting		$ (2)	(2,501)			(2,503)
Issuance of common shares for stock options exercised (in shares)		23
Issuance of common shares for stock options exercised		$ 1	135			136
Tax effect of share-based compensation			(2,327)			(2,327)
Net income (loss)					(95,784)	(95,784)
Foreign currency translation gain (loss)				(1,340)		(1,340)
Balance (in shares) at Jun. 30, 2015	[1]	120,403
Balance at Jun. 30, 2015	[1]	$ 1,204	987,538	$ (1,385)	$ 414,456	1,401,813
Issuance of common shares (in shares)		62,543
Issuance of common shares		$ 625	709,219			709,844
Share-based compensation			$ 8,902			$ 8,902

[1] Unaudited