Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended			3 Months Ended				9 Months Ended				0 Months Ended					9 Months Ended	52 Months Ended	9 Months Ended		111 Months Ended	9 Months Ended		95 Months Ended
	Jul. 16, 2014	Jun. 05, 2014	May 21, 2013	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		May 02, 2014 Regular Semi-Annual Dividend	Nov. 06, 2013 Regular Semi-Annual Dividend	May 21, 2013 Regular Semi-Annual Dividend	Nov. 04, 2014 Subsequent Event [Member] Regular Semi-Annual Dividend	May 17, 2010 2010 Stock Repurchase Program	Sep. 30, 2013 2010 Stock Repurchase Program	Sep. 30, 2014 2010 Stock Repurchase Program	Sep. 30, 2014 2005 401(k) Stock Repurchase Program	Sep. 30, 2013 2005 401(k) Stock Repurchase Program	Sep. 30, 2014 2005 401(k) Stock Repurchase Program	Sep. 30, 2014 2006 Director and Officer Repurchase Program	Sep. 30, 2013 2006 Director and Officer Repurchase Program	Sep. 30, 2014 2006 Director and Officer Repurchase Program
Schedule of Shareholders' Equity [Line Items]
Stock repurchase program authorized percentage																5.00%
Stock repurchase program amount authorized (in shares)																2,800,000
Stock repurchased during period (in shares)																	500,000	2,100,000	300,000	300,000	4,900,000	40,000	40,000	1,800,000
Aggregate price of shares repurchased since inception																		$ 21.3			$ 37.6			$ 14.0
Average price of shares repurchased since inception (per share)																		$ 9.95			$ 7.60			$ 7.76
Stock split, conversion ratio	1.5	1.5	1.5
Dividends declared (per share)				$ 0	[1]	$ 0	[1]	$ 0.09	[1]	$ 0.07	[1]	$ 0.09	$ 0.07	$ 0.07	$ 0.09

[1] Reflects three-for-two stock split effective July 16, 2014