Revised Financial Statements (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Out-of-period adjustment, net affect on after-tax income	$ 7,500
Retained earnings		$ 1,283,549			$ 1,247,485
Out-of-period adjustment net affect on diluted earnings per share (in dollars per share)		$ 0.03	$ 0.06	$ 0.06
Revision
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Retained earnings		$ (6,659)			$ (6,659)