CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 28,392	$ 27,303	$ 20,232	$ 83,697	$ 43,929
Other comprehensive income, net of tax:
Unrealized holding (loss)/gain on securities arising during the period, net of income taxes	[1]	(3,630)	(3,122)	(196)	(16,095)	7,153
Reclassification adjustment for net (gains) losses on sale of securities included in net income, net of income taxes	[2]	(834)	(240)	(588)	(1,079)	(1,956)
Other comprehensive (loss) income, net of tax		(4,464)	(3,362)	(784)	(17,174)	5,197
Comprehensive income, net of tax		$ 23,928	$ 23,941	$ 19,448	$ 66,523	$ 49,126

[1] Income tax (benefit) expense on the unrealized (loss)/gain on securities was $(1.6) million for the three months ended September 30, 2018, $(1.3) million for the three months ended June 30, 2018, $(253,000) for the three months ended September 30, 2017, $(6.8) million for the nine months ended September 30, 2018 and $4.7 million for the nine months ended September 30, 2017.

[2] Income tax (benefit) expense on the reclassification adjustment for net (gains) losses on sale of securities included in net income was $229,000 for the three months ended September 30, 2018, $90,000 for the three months ended June 30, 2018, $308,000 for the three months ended September 30, 2017, $320,000 for the nine months ended September 30, 2018 and $1.0 million for the nine months ended September 30, 2017.