Capitalized Software (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Capitalized Software
Capitalized software costs	$ 86,316	$ 82,877
Less: accumulated amortization	45,057	44,271
Total	41,259	38,606
Capitalization of software development costs	27,782	24,617	$ 26,003
Reduction in capitalized software costs and related accumulated amortization for fully amortized costs that are no longer in use	25,000
Capitalized software costs not subject to amortization	0	0
Amortization of capitalized software costs	$ 25,600	$ 25,100	$ 24,600