Acquisitions - Progressive Acquisition Pro Forma Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Business Acquisition [Line Items]
Revenues, as reported	$ 769,049	$ 662,490	$ 1,590,863	$ 1,247,913
Net earnings, as reported	$ 40,546	$ 8,505	$ 89,789	46,844
Progressive Finance Holdings, LLC
Business Acquisition [Line Items]
Revenues, pro forma				1,404,509
Net earnings, pro forma				$ 49,654