Investments Additional Disclosures Related to Associated Company Financial Statements (Details) - Investments in associated companies - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Summary of balance sheet amounts:
Current assets	$ 589,652		$ 589,652		$ 556,571
Noncurrent assets	139,934		139,934		160,202
Total assets	729,586		729,586		716,773
Current liabilities	294,784		294,784		257,559
Noncurrent liabilities	114,358		114,358		113,217
Total liabilities	409,142		409,142		370,776
Parent equity	320,444		320,444		345,997
Total liabilities and equity	729,586		729,586		$ 716,773
Summary income statement amounts:
Revenue	197,805	$ 269,715	418,872	$ 553,114
Gross profit	32,339	40,714	63,527	87,789
Loss from continuing operations	(8,146)	(5,049)	(6,256)	(3,204)
Net (loss) income after noncontrolling interests	$ (8,308)	$ 2,721	$ (1,313)	$ 5,170