Business Segments, Concentration of Business, and Credit Risk and Significant Customers (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Cash and cash equivalents	$ 237,125	$ 110,247	$ 263,606	$ 445,226
Consolidated total assets	1,259,729	1,068,064
Reportable segments
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Consolidated total assets	801,796	816,807	724,210
Unallocated to Segments
Reconciliations of total assets from reportable segments to the condensed consolidated balance sheets
Cash and cash equivalents	237,125	110,247
Unallocated deferred tax assets	35,632	30,662
Other unallocated corporate assets	$ 185,176	$ 110,348