Stockholders' Equity (Narrative) (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended			24 Months Ended	120 Months Ended	140 Months Ended
	Oct. 31, 2015	Jun. 30, 2004	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2004	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock Par Or Stated Value Per Share			$ 0.01			$ 0.01	$ 0.01		$ 0.01	$ 0.01	$ 0.01
Repurchase of common stock		40,032,366			40,032,366					40,032,366	41,995,355
Aggregate cost of common stock repurchase		$ 791,357			$ 791,357	$ 91,165	$ 7,317			$ 791,357	$ 882,521
Cash dividend per share			$ 0.145	$ 0.13		$ 0.535	$ 0.475	$ 0.415
Cash dividend per common share, increase	$ 0.015
Cash dividends on common stock						$ 65,990	$ 58,906	$ 51,213
Repurchase of common stock, maximum value			$ 1,200,000			1,200,000			$ 1,200,000		1,200,000
Remaining value of common stock authorized under repurchase program			$ 317,479			$ 317,479			$ 317,479		$ 317,479
Common stock, shares authorized but unissued			127,624,045			127,624,045			127,624,045		127,624,045
Total intrinsic value of stock options exercised						$ 1,241	$ 7,458	$ 5,729
Exercisable options to purchase common stock							37,000	274,902		37,000
2014 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance			3,250,000			3,250,000			3,250,000		3,250,000
2004 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance			7,162,500			7,162,500			7,162,500		7,162,500
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant expiration						2016
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant expiration						2020
Maximum [Member] | 2014 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term						10 years
Maximum [Member] | 2004 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term						5 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Assumed forfeiture rate			8.00%			8.00%			8.00%		8.00%
Vested deferred RSUs outstanding			256,191			256,191	223,752	163,995	256,191	223,752	256,191
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period end date						Dec. 31, 2017	Dec. 31, 2016
Percentage range of original shares granted depending on performance targets			50.00%			50.00%			50.00%		50.00%
Performance Shares [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award						1 year
Percentage range of original shares granted depending on performance against pre established targets			0.00%			0.00%			0.00%		0.00%
Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage range of original shares granted depending on performance against pre established targets			150.00%			150.00%			150.00%		150.00%
Executive Officer [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award						3 years			3 years
Assumed forfeiture rate			0.00%			0.00%			0.00%		0.00%
Officer [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of award						4 years
Assumed forfeiture rate			8.00%			8.00%			8.00%		8.00%