Notes Payable (Tables)

12 Months Ended

Dec. 31, 2013

Debt Disclosure [Abstract]

Schedule of debt

Notes payable are summarized as follows:

	December 31
	2013		2012
7.50% Convertible Notes, due 2016	$	55,500	$	55,500
7.50% Exchange Notes, due 2016	44,500		44,500
4.50% Convertible Senior Notes, due 2024	5,402		5,402
Total	$	105,402	$	105,402

Maturities of notes payable

 Maturities of notes payable at December 31, 2013 are as follows:  

	Total
2014	$	—
2015	—
2016	100,000
2017	—
2018	—
Thereafter	5,402
	$	105,402

Interest incurred, capitalized and expensed

	2013			2012			2011
Interest incurred	$	9,296		$	9,236		$	9,955
Interest capitalized	(6,466		)	(1,263		)	(439		)
Interest expense	$	2,830		$	7,973		$	9,516