Stockholders' Equity (Narrative) (Detail) (USD $)	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	1 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Net Share Settlements	Dec. 31, 2012 Net Share Settlements	Sep. 30, 2013 Restricted Stock	Dec. 31, 2012 Restricted Stock	Mar. 31, 2013 Three-Year Period	Mar. 31, 2012 Three-Year Period	Mar. 31, 2013 Four-Year Period	Mar. 31, 2012 Four-Year Period
Class of Stock [Line Items]
Common stock, shares authorized	80,000,000	80,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock issued from treasury stock	57,175	133,200
Issued common stock for the exercise of stock options		0
Restricted shares of common stock granted							432,400	646,438	262,000	179,000
Restricted shares of common stock vesting period, (in years)					3 years		3 years	3 years	4 years	4 years
Restricted stock granted	1,046,281					42,513
Percentage of target number of shares						25.00%
Treasury shares acquired, shares			256,811	357,714
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0