Stockholders' Equity - Additional Information (Detail) - USD ($)			1 Months Ended		12 Months Ended
	Sep. 19, 2016	Apr. 09, 2014	Jan. 31, 2015	Apr. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders Equity [Line Items]
Common stock, shares issued					91,861,054	90,320,374
Unvested shares of common stock					3,596,217
Treasury stock, shares					6,519,773	6,519,773
Cash dividends declared per share					$ 0.73	$ 0.84	$ 0.62
Dividends payable					$ 908,000	$ 430,000	$ 172,000
Dividends paid to stockholders					65,306,000	$ 72,318,000	72,113,000
Secondary offering costs							$ 747,000
Shares repurchased						2,413,803	2,605,970
Stock repurchased during period, total cost						$ 45,000,000	$ 65,708,000
Shares repurchased payment settlement during period			$ 5,650,000			50,650,000	60,058,000
Treasury stock at cost					154,871,000	$ 154,871,000	$ 109,871,000
Share Repurchase Program [Member]
Stockholders Equity [Line Items]
Shares repurchased						2,413,803	855,970
Share Repurchase Program, authorized amount							$ 250,000,000
Stock repurchased during period under Share Repurchase Program, average price per share						$ 18.62	$ 17.50
Stock repurchased during period, total cost						$ 45,000,000	$ 15,000,000
Share Repurchase Program, remaining authorized repurchase amount					$ 190,000,000
Stock Repurchase Program, number of shares repurchased					0
Secondary Offering [Member]
Stockholders Equity [Line Items]
Common stock, shares issued		0
Shares offered and sold by the selling stockholders		17,250,000
Shares repurchased				1,750,000
Underwriters Over-Allotment Option [Member]
Stockholders Equity [Line Items]
Shares offered and sold by the selling stockholders		2,250,000
2.75x Performance Restricted Shares [Member]
Stockholders Equity [Line Items]
Unvested shares of common stock					1,310,726	1,370,821
Accumulated dividends on unvested performance restricted shares					$ 3,690,000
Long-Term Incentive Performance Restricted Shares [Member]
Stockholders Equity [Line Items]
Unvested shares of common stock					212,369	62,365
Accumulated dividends on unvested performance restricted shares					$ 180,000
Dividends on shares probable of vesting					$ 18,000
Q3 2016 Declaration [Member]
Stockholders Equity [Line Items]
Cash dividends declared per share	$ 0.10				$ 0.10
Cash dividends declared date					Sep. 19, 2016
Cash dividends payable date					Oct. 07, 2016