Redeemable Preferred Stocks - Summary of Redeemable Preferred Stock (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Stockholders Equity [Line Items]
Accumulated dividends	$ 7,256
Series E Redeemable Preferred Stock [Member]
Stockholders Equity [Line Items]
Beginning balance	$ 202,169
Beginning balance, shares	139,768
Accretion relating to liquidation preference on preferred stock	$ 265
Accretion for discount and issuance costs on preferred stock	231
Accumulated dividends	7,256	$ 6,338
Ending balance	$ 209,921
Ending balance, shares	139,768