Stockholders' Equity (Detail) $ / shares in Units, $ in Millions	1 Months Ended		12 Months Ended
	Jun. 30, 2014 USD ($) shares	Jun. 30, 2009 $ / shares shares	Dec. 31, 2016 vote class $ / shares shares	Dec. 31, 2014 shares	Dec. 31, 2015 shares	Sep. 16, 2011 $ / shares shares
Class of Stock [Line Items]
Total stock dividend authorized to issue (in shares)			268,830,609
Number of classes of stock | class			4
Preferred stock, shares authorized			100,000,000
Preferred stock, par/stated value (USD per share) | $ / shares						$ 0.01
Shares in treasury stock | $	$ 25.0
Warrants exercised (in shares)			43,192
2009 warrants
Class of Stock [Line Items]
Warrants issued (in shares)		156,250
Exercisable price of warrants to purchase common stock (price per share) | $ / shares		$ 1.17
Number of warrants outstanding			40,057
Company Warrants
Class of Stock [Line Items]
Number of warrants outstanding			31,955
Equity Investment
Class of Stock [Line Items]
Number of warrants outstanding			1,000,000			1,000,000
Crestview Warrants
Class of Stock [Line Items]
Exercisable price of warrants to purchase common stock (price per share) | $ / shares						$ 34.56
Citadel Acquisition
Class of Stock [Line Items]
Warrants held in reserve for issuance (in shares)	300,000
Class A Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			93,750,000		93,750,000
Common stock, shares issued			32,031,054		31,987,862
Number of votes for each share | vote			1
Class A Common Stock | Citadel Acquisition
Class of Stock [Line Items]
Common stock, shares issued						9,000,000
Class A Common Stock | Minimum
Class of Stock [Line Items]
Class A common stock following conversion			4.99%
Class B Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			75,000,000
Shares converted into shares of Class A common stock				1,900,000
Class C Common Stock
Class of Stock [Line Items]
Common stock, shares authorized			80,609		80,609
Common stock, shares issued			80,609		80,609
Number of votes for each share | vote			10
Series A Redeemable Preferred Stock
Class of Stock [Line Items]
Preferred stock, par/stated value (USD per share) | $ / shares			$ 0.01