Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified			1 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jul. 31, 2011 IPO [Member]	Jun. 30, 2011 IPO [Member]	Jun. 30, 2012 IPO [Member]
Class of Stock [Line Items]
Common stock, shares authorized	500,000,000	500,000,000
Common stock, par value	$ 0.01	$ 0.01
Initial public offering, shares offered			28,750,000
Share price					$ 18
Underwriting discounts, commissions and other related offering expenses				$ 33.8