Stockholders' Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended		1 Months Ended	3 Months Ended			6 Months Ended
	Apr. 16, 2014	Jan. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Equity [Line Items]
Treasury shares acquired			38,424				446,271
Shares repurchased during period							$ 5.5
Common stock issued as a result of conversion							64,938
Stock repurchase program, amount			10	10			10
Dividends per share declared on outstanding common stock	$ 0.10	$ 0.10		$ 0.10		$ 0.08	$ 0.20	$ 0.16
Dividends payable date					Mar. 03, 2014		Jul. 03, 2014
Dividends payable, shareholders record date					Feb. 19, 2014		Jun. 19, 2014
Former Board of Directors Chairman [Member]
Equity [Line Items]
Treasury shares acquired							1,225,000
Shares repurchased during period							$ 14.7
Maximum [Member] | Former Board of Directors Chairman [Member]
Equity [Line Items]
Percentage of stock owned by Mr. Mier			5.00%	5.00%			5.00%
Series M [Member]
Equity [Line Items]
Conversion of preferred shares into common stock							8,000
Series A [Member]
Equity [Line Items]
Conversion of preferred shares into common stock							9,975