Fair Value Information - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, liabilities	$ 521,038	$ 469,587
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	0	0
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	14,692	30,181
Interest rate swaps, liabilities	14,692	30,181
Fair Value on Recurring Basis [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Total liabilities	0	0
Fair Value on Recurring Basis [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	2,827,040	2,429,104
Total liabilities	14,692	30,181
Fair Value on Recurring Basis [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	0	0
Total liabilities	0	0
Fair Value on Recurring Basis [Member] | Municipal Bonds [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Municipal Bonds [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	29,886	30,285
Fair Value on Recurring Basis [Member] | Municipal Bonds [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Residential Mortgage-backed Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Residential Mortgage-backed Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	2,191,338	1,904,935
Fair Value on Recurring Basis [Member] | Residential Mortgage-backed Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | CMO/REMIC - Residential [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | CMO/REMIC - Residential [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	590,166	462,814
Fair Value on Recurring Basis [Member] | CMO/REMIC - Residential [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Other Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Other Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	958	889
Fair Value on Recurring Basis [Member] | Other Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Investment Securities-AFS [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Investment Securities-AFS [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	2,812,348	2,398,923
Fair Value on Recurring Basis [Member] | Investment Securities-AFS [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	0	0
Fair Value on Recurring Basis [Member] | Interest Rate Swaps [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	0	0
Interest rate swaps, liabilities	0	0
Fair Value on Recurring Basis [Member] | Interest Rate Swaps [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	14,692	30,181
Interest rate swaps, liabilities	14,692	30,181
Fair Value on Recurring Basis [Member] | Interest Rate Swaps [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	0	0
Interest rate swaps, liabilities	0	0
Fair Value on Recurring Basis [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	2,827,040	2,429,104
Total liabilities	14,692	30,181
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	29,886	30,285
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Residential Mortgage-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	2,191,338	1,904,935
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | CMO/REMIC - Residential [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	590,166	462,814
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Other Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	958	889
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Investment Securities-AFS [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities - AFS	2,812,348	2,398,923
Fair Value on Recurring Basis [Member] | Carrying Value [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swaps, assets	14,692	30,181
Interest rate swaps, liabilities	$ 14,692	$ 30,181