Condensed Consolidated Statements Of Comprehensive Earnings - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net revenue:
Racing	$ 156.1	$ 155.4	$ 182.3	$ 179.2
Casinos	84.4	83.8	170.9	169.8
TwinSpires	68.2	60.7	117.6	106.1
Big Fish Games	125.2	104.5	247.3	196.4
Other Investments	4.4	4.5	8.4	8.1
Corporate	0.2	0.3	0.4	0.5
Total net revenue	438.5	409.2	726.9	660.1
Operating expense:
Racing	72.3	75.1	107.9	111.3
Casinos	60.4	61.0	121.4	122.1
TwinSpires	41.4	38.1	76.0	70.7
Big Fish Games	105.6	83.4	215.0	165.6
Other Investments	4.1	3.9	8.0	7.7
Corporate	0.4	0.8	1.0	1.8
Selling, general and administrative expense	24.6	22.1	47.7	43.6
Research and development	9.7	9.9	20.5	20.1
Calder exit costs	1.5	0.8	1.9	0.8
Acquisition-related charges	1.1	8.2	3.8	14.6
Total operating expense	321.1	303.3	603.2	558.3
Operating income	117.4	105.9	123.7	101.8
Other income (expense):
Interest income	0.0	0.0	0.0	0.2
Interest expense	(11.1)	(7.1)	(21.7)	(14.6)
Equity in income of unconsolidated investments	4.8	2.9	8.6	5.9
Miscellaneous, net	0.4	0.0	(0.1)	5.6
Total other income (expense)	(5.9)	(4.2)	(13.2)	(2.9)
Income before income tax provision	111.5	101.7	110.5	98.9
Income tax provision	(41.7)	(46.6)	(37.9)	(45.4)
Net income	$ 69.8	$ 55.1	$ 72.6	$ 53.5
Earnings Per Share, Basic [Abstract]
Basic	$ 4.16	$ 3.12	$ 4.32	$ 3.04
Earnings Per Share, Diluted [Abstract]
Diluted	$ 4.11	$ 3.10	$ 4.27	$ 3.02
Weighted average shares outstanding:
Basic	16.5	17.3	16.5	17.3
Diluted (in shares)	17.0	17.7	17.0	17.7
Other comprehensive income (loss):
Foreign currency translation, net of tax	$ 0.2	$ (0.1)	$ 0.2	$ (0.4)
Other comprehensive income (loss)	0.2	(0.1)	0.2	(0.4)
Comprehensive income	$ 70.0	$ 55.0	$ 72.8	$ 53.1