Stock-Based Compensation - Stock Options (Details) - $ / shares	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Options
Beginning balance (in shares)	375,086	401,223
Granted (in shares)	0	0
Exercised (in shares)	(3,677)	(25,586)
Forfeited or expired (in shares)	0	0
Ending balance (in shares)	371,409	375,637
Weighted Average Exercise Price
Beginning balance (in dollars per share)	$ 31.64	$ 31.96
Granted (in dollars per share)	0	0
Exercised (in dollars per share)	32.96	36.70
Forfeited or expired (in dollars per share)	0	0
Ending balance (in dollars per share)	$ 31.63	$ 31.63
Stock Options, Time Based
Options
Ending balance (in shares)	320,528	323,101
Weighted Average Exercise Price
Ending balance (in dollars per share)	$ 32.91	$ 32.94
Stock Options, Performance Based
Options
Ending balance (in shares)	50,881	52,536
Weighted Average Exercise Price
Ending balance (in dollars per share)	$ 23.58	$ 23.58