Unaudited Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Premises and equipment, accumulated depreciation and amortization	$ 85,679	$ 82,233
Identified intangible assets, accumulated amortization	$ 39,420	$ 38,752
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	85,177,172	85,177,172
Treasury stock, shares (in shares)	7,034,754	6,525,783
Unallocated common stock held by ESOP, (in shares)	31,278	51,114