Note 13 - Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Year Ended December 31,
	2016		2015			2014
	(Dollars in thousands)
Current tax provision (benefit)
Federal	$	32,102	$	2,549		$	1,631
State		323		(249	)		1,475
Total current		32,425		2,300			3,106
Deferred tax provision:
Federal		10,960		30,268			28,630
State		5,185		3,065			5,596
Total deferred		16,145		33,333			34,226
Provision for income taxes	$	48,570	$	35,633		$	37,332

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Year Ended December 31,
	2016			2015			2014
	(Dollars in thousands)
Tax expense computed at federal statutory rate	$	53,123		$	35,498		$	35,166
State income tax expense, net of federal benefit		4,553			3,043			3,340
Other permanent differences		(647	)		(935	)		(1,435	)
Domestic manufacturing deduction		(5,563	)		(39	)		-
Expiration of state net operating loss		-			336			3,030
Tax expense (benefit) related to an increase (decrease) in unrecognized tax benefits		75			(479	)		559
Charitable contributions statute expiration		-			-			181
Federal energy credits		(3,428	)		(1,058	)		(1,131	)
Rate changes		-			48			866
Change in valuation allowance		253			(549	)		(1,665	)
Other		204			(232	)		(1,579	)
Provision for income taxes	$	48,570		$	35,633		$	37,332
Effective tax (benefit) rate		32.0	%		35.1	%		37.2	%

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31,
	2016			2015
	(Dollars in thousands)
Deferred tax assets:
State net operating loss carryforwards	$	26,015		$	31,292
Alternative minimum tax and other tax credit carryforwards		12,325			31,993
Stock-based compensation expense		18,228			20,068
Warranty, litigation and other reserves		14,155			9,470
Receivables from related party		7,626			8,342
Accrued compensation		7,330			7,241
Asset impairment charges		6,456			5,049
Inventory, additional costs capitalized for tax purposes		6,498			5,894
Other, net		2,993			2,429
Total deferred tax assets		101,626			121,778
Valuation allowance		(13,803	)		(12,868	)
Total deferred tax assets, net of valuation allowance		87,823			108,910
Deferred tax liabilities:
Property, equipment and other assets		4,276			4,739
Deferred revenue		1,400			2,312
Unrealized gain on marketable securities		4,676			671
Other, net		2,583			2,081
Total deferred tax liabilities		12,935			9,803
Net deferred tax asset	$	74,888		$	99,107

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	Year Ended December 31,
	2016			2015			2014
	(Dollars in thousands)
Gross unrecognized tax benefits at beginning of year	$	488		$	905		$	371
Increases related to prior year tax positions		156			139			633
Decreases related to prior year tax positions		-			(475	)		(85	)
Lapse of applicable statute of limitations		(67	)		(81	)		(14	)
Gross unrecognized tax benefits at end of year	$	577		$	488		$	905