Derivatives and Hedging Activities - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) Contract $ / shares shares	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Contract $ / shares shares	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) shares	Dec. 01, 2016 USD ($)
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset	$ 14,100,000		$ 14,100,000			$ 10,800,000
Business Acquisitions, Purchase Price Allocation, Subsequent Years, Remaining Adjustments	$ 1,600,000		1,600,000
Marked To Market Adjustment On Derivative Instruments			$ 1,700,000
Preferred Stock, Shares Issued | shares	867,846		867,846
Preferred Stock, Redemption Price Per Share | $ / shares	$ 50.00		$ 50.00
Credit Default Option [Member]
Derivative [Line Items]
Credit Risk Related Contingent Features Termination Value	$ 3,800,000		$ 3,800,000
Net Liability Position [Member]
Derivative [Line Items]
Credit Risk Related Contingent Features Termination Value	3,800,000		3,800,000
ERROR in label resolution.
Derivative [Line Items]
Fair Value of Credit Risk Derivatives	$ 3,600,000		$ 3,600,000
Designated as Hedging Instrument [Member] | Interest Rate Caps
Derivative [Line Items]
Derivative, Number of Instruments Held | Contract	2		2
Derivative, Notional Amount	$ 50,000,000		$ 50,000,000
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Number of Instruments Held | Contract	10		10
Derivative, Notional Amount	$ 550,000,000		$ 550,000,000
Designated as Hedging Instrument [Member] | Interest Expense
Derivative [Line Items]
Loss on Cash Flow Hedge Ineffectiveness	(11,000)	$ (120,000)	(14,000)	$ (163,000)
Change in fair value of interest rate derivatives included in AOCI and expected to be reclassified in the next 12 months			(100,000)
Other Assets [Member]
Derivative [Line Items]
Interest Rate Cash Flow Hedge Asset at Fair Value	1,897,000		1,897,000		$ 2,364,000
Interest Rate Swap [Member]
Derivative [Line Items]
Fair market value of interest rate swaps	$ 7,562,000		7,562,000		$ 3,626,000
Changes Measurement [Member]
Derivative [Line Items]
Embedded Derivative, Fair Value of Embedded Derivative Asset						$ 3,300,000
Parent Company [Member]
Derivative [Line Items]
Marked To Market Adjustment On Derivative Instruments			$ 6,757,000	$ (1,407,000)
Preferred Stock, Shares Issued | shares	867,846		867,846		867,846
Interest Rate Cash Flow Hedge Asset at Fair Value	$ 1,897,000		$ 1,897,000		$ 2,364,000
Fair market value of interest rate swaps	$ 3,626,000		$ 3,626,000		$ 7,562,000