Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 199,738	$ 157,870	$ 98,387
Unrealized holding gains (losses):
Before tax	61,818	(16,294)	12,641
Tax effect	(17,218)	4,342	(5,077)
Net of tax	44,600	(11,952)	7,564
Reclassification of net losses included in net income:
Before tax	0	0	(1,876)
Tax effect	0	0	771
Net of tax	0	0	(1,105)
Net unrealized holding gains (losses)	44,600	(11,952)	8,669
Derivative Instruments
Before tax	4,670	2,786
Before tax			(4,333)
Tax effect	(1,301)	(789)
Tax effect			1,746
Net of tax	3,369	1,997
Net of tax			(2,587)
Net unrealized holding gains (losses):
Before tax	3,624	(3,850)	2,988
Tax effect	(1,035)	1,018	(1,196)
Net of tax	2,589	(2,832)	1,792
Total other comprehensive income (loss)	50,558	(12,787)	7,874
Total comprehensive income	$ 250,296	$ 145,083	$ 106,261