Preferred Stock - Additional Information (Detail) (USD $)						0 Months Ended						0 Months Ended
	Sep. 30, 2014	Jul. 29, 2014	Apr. 29, 2014	Sep. 30, 2014 Preferred Stock [Member]	Apr. 29, 2014 Maximum [Member]	Jul. 29, 2014 Non-Voting Series A Preferred Stock [Member]	Apr. 30, 2014 Non-Voting Series A Preferred Stock [Member]	Apr. 29, 2014 Non-Voting Series A Preferred Stock [Member]	Jul. 29, 2014 Non-Voting Series A Preferred Stock [Member]	Apr. 30, 2014 Non-Voting Series A Preferred Stock [Member]	Oct. 27, 2014 Subsequent Event [Member]	Oct. 27, 2014 Subsequent Event [Member] Non-Voting Series A Preferred Stock [Member]	Oct. 27, 2014 Subsequent Event [Member] Non-Voting Series A Preferred Stock [Member]
Class of Stock [Line Items]
Issuance of non-voting Series A Preferred Stock, shares issued										9,000
Additional shares issued									1,800				1,800
Non-voting Series A Preferred Stock, shares purchased price									$ 18,000,000	$ 90,000,000			$ 18,000,000
Non-voting Series A Preferred Stock, number of shares issued		1,800	1,800		18,000						1,800
Amount Of Non Voting Series A Preferred Stock Purchase price						18,000,000		18,000,000				18,000,000
Non-voting Series A Preferred Stock, maximum aggregate consideration			180,000,000
Non-voting Series A Preferred Stock, cumulative, non-participating cash dividend							0.10%
Redemption of Preferred Stock at original purchase price	$ 10,000
Estimated fair value of derivatives				$ 3,000,000