Dividend and Equity Distribution (Details) - $ / shares	9 Months Ended
	Sep. 30, 2015	Jun. 08, 2011
Dividend and Equity Distribution
Estimated option forfeiture rate (as a percent)	2.00%
Holders of options expected to vest in Parent's stock | Parent
Dividend and Equity Distribution
Dividend declared (in dollars per share)		$ 0.12
Estimated option forfeiture rate (as a percent)	2.00%