CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income		$ 41,375	$ 38,527	$ 28,392	$ 118,620	$ 83,697
Other comprehensive income, net of tax:
Unrealized holding gain (loss) on securities available-for-sale arising during the period, net of income taxes	[1]	10,864	17,449	(3,630)	39,280	(16,095)
Reclassification adjustment for net gain on sale of securities included in net income, net of income taxes	[2]	(3,027)	(151)	(834)	(3,484)	(1,079)
Other comprehensive income (loss), net of tax		7,837	17,298	(4,464)	35,796	(17,174)
Comprehensive income, net of tax		$ 49,212	$ 55,825	$ 23,928	$ 154,416	$ 66,523

[1] Income tax expense (benefit) on the unrealized gain (loss) on securities was $4.4 million for the three months ended September 30, 2019, $7.7 million for the three months ended June 30, 2019, $(1.6) million for the three months ended September 30, 2018, $16.0 million for the nine months ended September 30, 2019 and $(6.8) million for the nine months ended September 30, 2018.

[2] Income tax expense (benefit) on the reclassification adjustment for net gains (losses) on sale of securities included in net income was $1.2 million for the three months ended September 30, 2019, $61,000 for the three months ended June 30, 2019, $229,000 for the three months ended September 30, 2018, $1.4 million for the nine months ended September 30, 2019 and $320,000 for the nine months ended September 30, 2018.