Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Balances of AOCI Including Current Period Other Comprehensive Income (Loss) and Reclassifications Out of AOCI (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	[1]	$ 2,960,954	$ 2,885,104	$ 2,967,940	[2]	$ 2,808,663
Beginning Balance						(23,547)
Other comprehensive income (loss) before reclassifications		24,492	4,830	42,684		18,692
Less: gain (loss) reclassified from AOCI		4,808	5,523	9,286		(2,921)
Tax effect		(120)	(338)	(1,666)		(226)
Net current-period other comprehensive income (loss)		19,564	(1,031)	31,732		21,387
Ending Balance		3,074,405	2,914,945	3,074,405		2,914,945
ASU 2018-02
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Impact of change in accounting principle								$ (586)
Unrealized Gains (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		14,181	2,568	7,201		(20,232)
Beginning Balance						(20,232)
Other comprehensive income (loss) before reclassifications		23,973	3,355	35,431		17,711
Less: gain (loss) reclassified from AOCI		4,808	5,523	9,286		(2,921)
Tax effect		0	0	0		0
Net current-period other comprehensive income (loss)		19,165	(2,168)	26,145		20,632
Ending Balance		33,346	400	33,346		400
Unrealized Gains (Losses) on Cash Flow Hedges | ASU 2018-02
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Impact of change in accounting principle								0
Unrealized Gains (Losses) on Available for-Sale Debt Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		3,271	(3,686)	(1,917)		(2,722)
Beginning Balance						(3,308)
Other comprehensive income (loss) before reclassifications		522	1,475	7,256		985
Less: gain (loss) reclassified from AOCI		0	0	0		0
Tax effect		(120)	(338)	(1,666)		(226)
Net current-period other comprehensive income (loss)		402	1,137	5,590		759
Ending Balance		3,673	(2,549)	3,673		(2,549)
Unrealized Gains (Losses) on Available for-Sale Debt Securities | ASU 2018-02
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Impact of change in accounting principle								(586)
Other
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(13)	(11)	(13)		(7)
Beginning Balance						(7)
Other comprehensive income (loss) before reclassifications		(3)	0	(3)		(4)
Less: gain (loss) reclassified from AOCI		0	0	0		0
Tax effect		0	0	0		0
Net current-period other comprehensive income (loss)		(3)	0	(3)		(4)
Ending Balance		(16)	(11)	(16)		(11)
Other | ASU 2018-02
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Impact of change in accounting principle								$ 0
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	[1]	17,439	(1,129)	5,271		(22,961)
Impact of change in accounting principle							$ (586)
Ending Balance		$ 37,003	$ (2,160)	$ 37,003		$ (2,160)

[1] The beginning balances for the nine-month periods were derived from the audited Consolidated Financial Statements included in Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019.

[2] December 31, 2018 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019.